Seems like Epic want everyone under Unreal Engine,not exactly an amazing thing to see, because it leads to that nice monopoly people like to fight against, but not entirely fight against.
Also, if I am correct, Grants are meant to be paid back over time in some way or another. Devs get to own their IP, but not the engine that runs it.
Grants are not meant to be paid back.
To be fair, a lot of people already use Unreal Engine.