Coding is like magic. People makes programs and codes. But no-one really knows why it works or how exactly it works. It's basically unicorn shit. Be happy that it works. And sometimes it doesn't.
Dude, AMD cards these days are already comes from the factory at their limit. Because they try to match their gaming performance with Nvidia's. (and still fail). But in terms of raw performance (0/1), those are beasts.
He can use whatever he wants, mostly because he has the capability to program that device whatever way he wants. Just like custom Linux distros for specific tasks. Unlike mediocre people like us.
GPUs won't replace CPUs. But CPU architecture will change. X86 is close to it's end. Multicore is the way to go. But still it will be a multicore CPU, not a GPU.
If price is similar, then I would get it. Because why not. And most North American students can get a free copy of windows 8, 10 and server 2016 anyway.