As to pros/cons: Con:

• you need equipment, I. E. You have more stuff standing around.
• you need to find a place to setup the projector permanently or go through the hazzle of doing it every time manually

Pro:

• TL/DR; Boost in productivity
• you safe so much time
• in the long run you save money (don’t need to print anymore, need a lot less chalk)
• you need no printer anymore
• you can perfectly align all your pieces beforehand in inkscape, then minimize the leftovers
• less time spent with stuff you don’t like to do (cut the pattern, bring pattern on the fabric) and a lot more time spent with stuff you want to do (actual sewing)

By now I just take photos of all the scrap pieces I have, with a metering tool lying around it (similar to old csi crime scene photos). That way I can judge quickly whether any leftovers I have are large enough to fit the pattern, which saves even more time :)