It is definitely an over-statement to say that UE4 is free to use in non-game uses. It’s accurate to say that it’s free to use if the use falls within a royalty exception in the EULA sections 5(1-9).
The FAQ is referring to the free uses of the EULA I referenced above. Still, I can see how it could be seen as misleading so I’ll take a look into that further and see if we an clear it up.