Insignificant compared to the total time removing the wheel, removing the tire, finding the source of the flat, replacing the tube, mounting the tire, then under a minute to inflate (typical for me), put the wheel back on, check the brakes...

Unless you're trying to place in your age group in a triathlon or more competitive than that, I don't see the point. I've pulled over to help out people that screwed up inflating with a CO2 cartridge maybe half a dozen times. You get one shot with a cartridge to get it right.

CO2 cartridges and bottled water, solutions in search of a problem. Air and water are free for the taking.