Grants are not meant to be paid back.
To be fair, a lot of people already use Unreal Engine.
Then I wonder just how many years they can keep that up. I'd hate to see it being sued now and dumped later, like a lot of other companies do in time.
A lot of people also use Unity and other engines, especially over the years. It's nice to see some variety in engine use, than just everyone hailing under EG one engine.