One advantage is that it won’t work without CO2 cartridges. Can kids buy those at the store? Obviously you need to teach the kid that it could be mistaken for a real gun.
Yes, Co2 cartridges can be purchased by anyone but now a days they're used by bicyclists who need a quick fill for a flat tire...........
I have a hand held CO2 quick fill that I use to top off my volleyballs...........