It's open-source & MIT-licensed; if it's better than Unity's GI -- and it IS better, because Unity does not currently have ANY realtime-GI solution in their latest versions (they stopped licensing Enlighten for current/2020.x+ versions) -- so why wouldn't Unity just implement this, too?
There's nothing that appears to be stopping them from doing so, other than pride perhaps; part of me really, really hope that they'll do exactly that, though I've yet to dive into the code to see how viable it may or may not be given Unity's current SRP situation(s).