It expands their empire like Microsoft pledging to "support" Open Source: it's disingenuous, self-serving, and develops a "claim" of authority over the sector. It allows them, the makers of Unreal Engine, to develop a business relationship with their competition and influence the trajectory on one of only major alternatives in order to control the market more.
If Epic Games really cared about Godot, they would align more with their values in-house. Their M&A drives the organization like a propeller.
The other option is Epic is the same as now but Godot gets no money