Its value is non-zero, but not far above it, at least with an Xbox.
Why? First of all, let's remember the VRR range is limited. That means 48-60 hz. Most games are well below that. Most games have some form of vsync, which works great. And most games don't support it properly.
If you were talking about a PC, then that would be different because you have more control over it and can make better use of it, but even then I'd say it's only crucial for a couple of games where vsync doesn't work right (though then chances of VRR working right are also not great either). The biggest gain with VRR is lower input lag compared to vsync (as a solution to screen tearing). So unless you're a very competitive gamer, it doesn't matter (and in that case you'd use a monitor anyway).
Definitely buy the XG95 over the Q90R. Whatever supposed advantages the latter has are totally neutered in game mode anyway, while the Sony doesn't gimp itself when used for games/PC.