I have a few different C02 inflators and haven't used them in more than 5 years. Why? The reliability factor and air on demand requirement. I cannot tolerate a tool that doesn't work when it HAS to work. C02 inflators fall into that category.
Now some will say that pumps can break, seals can fail, etc. In 47 years or road riding under my belt, I have had zero pump failures on a ride. In that time I've probably had to repair or swap tubes 25 or 30 times by the side of the road. Every single time the pump worked perfectly. In about 10 years of riding with C02 inflators, I have had two inflators go flat, for no reason at all. They just sat in my seat bag waiting for a flat tire. Thank goodness I still carried my pump so I got home!!
Not a fan of C02 inflators. I have some nice ones too! Anyone want to make me a deal on the whole lot? I have Silca, Lezyne and a couple of other "high-end" inflators plus a dozen or more C02 cylinders. Can't guarantee they will work though......