I mean seriously, what's the point? He can play the drums himself. And how do those things work?

They are an instrument that CAN be played in real time, as well as step time programmed. They are a technological tool that can be utilized. If drum machines are to be rejected then I say reject digital recording, computers, mastering, signal processing...the whole recording process. I think as an artist Prince should explore all avenues, both real drum kits, triggers, and rhythm or drum machines. We shouldn't limit him.
Sometimes the sound a songwriter is looking for isn't in a trap set. Drum machines have opened up a plethora of inspiration, ideas and creativity just as keyboard/synths have.

I may get some flack from some people here, but even though I am not a rap fan per se, there is definitely an art even to mixing and scratching. I watched some dj's scratching on a program that documented how rap and hip-hop came about and I gained a respect for their techniques. I would classify scratching as a rhythmic, percussive instrument.