Shoot at a ghast with a mining laser. Miss a bit. Unload a lava lake over your head. Yup, working as intended.
Shoot at a ghast with a bow. Oh yeah, gravity. He'll wait for the next shot. Plink a zombie pig instead. Well hell, there goes that picnic I was planning. At least his family will eat well.
Shoot anything, and I mean anything, with a MAIMER. Hit, it's dead. Just dead, not limping and pissed off. It might have even vaporized whatever the poor thing may have dropped, but you're alive. Miss, no lava rains down on your head, you aren't buried in sand, not even a chipped block. Seems the projectile is superheated and disintegrates on contact with solid or granular matter. Well, that cost a bit but you can try again.
Almost forgot... the nano saber would definitely not lose usefulness. It's a lot cheaper to use, albeit a much shorter range. Costs less on a miss too, so you won't have to worry about swinging wildly or being forced to wear a Lappack instead of that nifty Quantum Armor you saved up for.