It might be useful if youre fully booked... All the set up time it saves to use the cartridge system and the little space that is necessary for one machine and a couple of cartridges are fantastic.

The price difference for me would be too big. I pay like 1,70€ for a needle and grip and the cartridge costs about 3€ setting up 4-5 machines for a tattoo its gonna cost too much more to consider