I'm just getting back into cycling, but back in the day (10 - 15 years ago) I didn't get flats often enough to care about the cost of inflator cartridges. I started with a frame pump that was supposed to fit my frame, but the first time I rode with it I hit a bump, it fell off, and I ran over it with the back tire and ruined the pump (not saying that this is typical or that frame pumps are bad, just my experience). If the inflator has a control valve (the one I used to have was just a tube with threads at both ends for the valve stem and cartridge, and something to puncture the end of the cartridge when you screw it in) I would think you could get away without a pump at all. I just bought a new one with a control valve but haven't had occasion to use it yet. I can see why people would want a pump for long rides/tours/middle-of-nowhere though.