It does feel like an afterthought.
If they really want to push this through, they would make staying with an old license as inconvenient as possible. If they don’t, they risk turning 5.3 into a sort of evergreen version for non-game users.
A lot of non-game uses tend to have rather narrow needs, there isn’t necessarily a reason they’d need to use Unreal Engine specifically. But, since it was there and available, why not. Like that artist who they featured at some point using UE to create backgrounds for 2D art.
One of the advantages of the Unreal Engine license was that compared to i.e CryEngine, which bans everything that’s not a game for entertainment purposes, in UE you could, for example, make a game, and then use the same assets in the engine to make an animation or whatever.