OP, the inflator you pictured is probably fine and if it will take non-threaded cartridges, is a bit more versatile than just the mini inflators. But threaded cartridges are not at all hard to find, and the inflator heads are a lot less bulky. Two cartridges would be fine and is good practice to carry as backup; one cartridge would get you up to 35psi or so, more than enough to get you going in an emergency, to the nearest place you could top up your pressure.

Lately, I've only been carrying a CO2 cartridge and mini inflator. Used to carry a pump, then a hybrid pump/CO2 inflator, now just the inflator. All my bikes have puncture protection tires and flats are extremely rare.

The hybrid inflator I carried looks like this:


It is an extremely compact pump, so I carried it in a bag with one cartridge, instead of bolted underneath a waterbottle cage with the bracket shown here. Because it is so compact, it really is just a backup to the inflator. I never actually had to use the pump, only ended up using the inflator a few times, and since that ended up being the case, I feel confident just carrying an inflator now.

Upshot is that you can repair a flat very quickly, since pumping with a micro- or mini-pump takes a while vs. nearly instantaneous fill with the inflator/cartridge. Downside is it's a one-shot deal, so you better get it right the first time or be carrying an extra cartridge or two.

I'd advise wasting a cartridge to try it out and do a practice run at home before having to use it for real at the side of the road, and always offer such an opportunity to students who take my roadside flat repair class at the shop.