The major benefit is simply avoiding all kind of crashes which plague many games.

That is another thing that sadly many game developers usually don't care that much, given time to market.

Which is surprising, since games are very much human faced, and those crashes is what's considered reducing the value quite a bit. So using something like Rust should be a big boon for game developers. The only issue is that some things will still remain in the unsafe area (i.e. interfacing with graphics backend and such), but at least the code that developers control can be safer.