Cartridge inflation is useful when you need save space, weight, and time. I keep a fresh tube and inflator system ready to go on my road bike that has scarce room for a pump. Otherwise, this is a commodity product that does what it's supposed to do.
I have not found these cheaper anywhere else, not even close. So they don't have a sticker on the outside making the cartridge flashy, who cares? It's gonna stay in your repair kit until you're sitting on a dirty sidewalk or on the side of some dusty trail with your tire in your lap. They're a steal! One cartridge fills one tire, nice and simple.
I pumped my 700 X 23 tire up to at least 115, so I could keep riding after a flat. One issue with CO2 is that it depletes ozone, so I take one less ride in the car to compensate. Another issue is whether you can recycle the spent cartridges where you live.
you can't underestimate the value of a CO2 cartridge in your seatbag. you can spend 5 minutes with a frame pump working up a sweat while your group ride waits for you, or you can use one of these. well worth the pennies