I'm sure someone could think of an "interesting" game built off of this data but I highly doubt you go through all this engineering effort on that idea alone.
It goes further than that now. For The Mandalorian, they famously set up a "20-foot high, 270-degree semicircular LED video wall"[0] to use as a backdrop for the shots, and that wall was rendering the desired environment using Unreal Engine. No need to chroma key an alien planet in post, when you can make it a part of the scene (and now the actors can see it too as they play!). More at [1].
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[0] - https://www.polygon.com/tv/2020/2/20/21146152/the-mandaloria...
[1] - https://www.unrealengine.com/en-US/blog/forging-new-paths-fo...
But the LED video walls serve two purposes: ensure the lighting and reflections on real objects in the scene match up with the CGI, and give the actors a visualisation to work with.
All the videos and reels I've seen on this talk about "capturing the effects in-camera", so while I wouldn't be surprised if there's some integration and cleanup work to be done (particularly where the wall meets the set), it does sound like what is on the LED wall is what we see in the final footage and it's not just placeholder or pre-viz.
It's also used to create TV studios [0]. In the UK, BBC soccer punditry programmes such as 'Match of the Day' are filmed in a green-screen studio with the pundits, desk and chairs, and a virtual studio created using Unreal Engine. Different programmes can get a totally different look by using different Unreal environments.
[0] https://www.unrealengine.com/en-US/industry/broadcast-live-e...
If you were trying to build a virtual version of a real-world location, I would imagine the time savings in starting from real landmarks and buildings would be significant.