I used one of these while making the transition from pump to CO2. Or the Bontrager equivalent, anyway. My thinking was that I'd have a pump as backup if the CO2 inflation ever failed, multiple flats in a day, etc.--all the horror stories the pump-only crowd like to scare us with.

What I found was that through a few flats, I only ever used the inflator part of it, never had to use the pump as backup. It was useful for getting me over my CO2 reticence/pump prejudice.

Compromises: Not as small/light as just an inflator head, but works just as well. Not that I ever used it, but the pump is not as good as a standalone super-pump like the ubiquitous Road Morph, probably on par with the micro-mini pumps, but with the weight and volume disadvantage of having an inflator built in and bringing along cartridges.

It's like a CO2 inflator with training wheels.

Last flat I got happened this spring a few days before the weekend I'd planned on switching the 26x1.95 Town and Countries I use at the beginning and end of the riding season. I had 2 CO2 cartridges, an inflator, a minipump, a spare tube and a patch kit with me giving me many choices on how to deal with the flat. Instead of fixing it then and there and then changing it again over the weekend when I put the 26x1.5 slicks I usually use I opted to put on the jacket I carry in case I have to stop to make a repair before walking home. I got half way home when I got so hot I had to stop and take the jacket off. I guess you can be overprepared.

All the more reason to stock up on the cartridges now.

So far as I know, commercial CO2 is taken from stack gasses at power plants, etc., it's CO2 that would otherwise be wasted to the atmosphere anyway. While used in CO2 cartridges, it's also used as a shielding gas in welding processes, and that's probably a bigger application for it. But it shouldn't contribute to global warming, etc.
But, the reason I jumped into this old thread- I'm a Pump kind of a guy. Except on last week's ride, I broke the shaft on my Road Morph. Fortunately, I had the tire up to about 75 psi, and we were able to ride it on in. That's the second Road Morph I've broken, though. If you assume that pumps are more reliable than something else- well, that may not be the case.
One other time, I rode around for 6 months and finally discovered the pump in my bag was missing the little tip and was essentially useless, but I discovered that prior to needing it.
I've rescued one or two other people with non-working pumps, also.
Asking around in the local club, everyone was telling me, "Oh, I carry a pump AND CO2", "Oh, I carry a pump AND a minipump for backup", etc.
As a side note, I've been carrying a spare tire on the tandem for 3 or 4 years, and finally used it last spring. But in that same time, I've seen and experienced multiple pump failures. So based on that experience, a backup pump/CO2 is probably more likely to be useful than a spare tire.
I'm planning to replace the Road Morph with another one, but will also carry CO2 now.

I carry a micro hand pump that takes about 150 pumps to get up to a decent pressure on a 700x23 tire so I also carry a CO2 pump that takes the non threaded cartridges for speed and ease of use.

If you drop a dime in the cartridge holder, you can use the inexpensive BB gun cartridges that can be had for about $0.50.

The 12 gram cartridge works perfectly to bring a 700x23 tire up to 100psi in an instant.

As it turns out, I had a flat on my morning commute today and it worked great.

I too have had multiple flats in a single ride so that's why I carry the hand pump.

threaded or non threaded which is better? i alway try to install my CO2 and majority of it seems to freeze my fingers and not go into the tube. what am I doing wrong?

I own this one Genuine Innovations Ultraflate Plus Inflator with 16g Non-Threaded Cartridge - Modern Bike

It can take threaded and non-threaded. Only a little escapes when you put a new cartridge in and the sleeve protects your hand from freezing when you use it.

I like this one. Lezyne trigger drive. Nice and compact. around $20 with a cartridge. CNC machined aluminum with brass internals and comes with a neoprene sleeve for the cartridge that keeps your hand from getting cold.

I've never had that bad of luck with road morphs, but if I had, I'd consider getting one of the various similar pumps from other companies. Yikes lol. That is some bad luck.

I believe Lezyne makes a road-morph-clone with a metal body, perhaps it would be more durable for you.

I have that, and I also have one from Crank Bros https://www.crankbrothers.com/pumps_co2kit that I actually like better because even though the Lezyne one comes with a sleeve that goes around the cartridge, you still have to put a finger on the inflator to press down to engage it, and that part gets frosty as well.
But on the Crank Bros one there are handles to keep your fingers off the inflator.

for the record, on my main commuter bike I carry a lezyne pressure drive pump, and 1 co2 cartridge. But in ~3 years of commuting, I've only had 2 flats.

I've never had any "bad luck" with a decent pump...

That is about my track record. A CO2 inflator sure is a lifesaver in the hot summer or cold -I have had flats in the summer with a hand pump and with a CO2 inflator and it is a big difference. I haven't used the Lezyne on my bike yet, but have used in a stranded cyclist.

Opinions vary. I've had flat in the summer and flats with bugs, and a road morph did the job in only very slightly less time than a CO2 cartridge. The time to take off and fix the tire is much longer than the inflate time if you're not using a super tiny pump.

I use a Genuine Innovations inflator. It's well made and easy to use. I buy cartridges in bulk from whoever has em cheaper on Ebay.

i'll just say this...

i have two CO2 inflaters. they have both been on my closet shelf now for about two years. it might have had something to do with almost freezing my index finger while simultaneously exploding a tube, but i don't remember exactly. anyway, i now carry a patch kit and a marginally effective hand pump.

i have no idea why i bought the second one.

Normally they come with a little foam 'condom' to protect your fingers.

no condom... i was ridin' bareback.