They ALL fake GI, even something like VXGI is a hack, it’s far more accurate than the dynamic GI systems that games have these days, but it’s not comparable to baked GI. What most games do to fake GI–they use a very small sample of GI that they can quickly calculate to add some light into the shadows which will make it look much nicer. But it’s nowhere near a full dynamic GI solution.
And no, the dynamic lighting system in UE4 isn’t useless, games like ARK use it since there’s no other way to do day/night cycles and it would be too much data anyway for a large game like that. Epic is using a fully dynamic solution for Fortnite, Eve: Valkyrie is using dynamic lighting as well.