This is probably not a huge improvement for Steam gamers with Proton. I would like to see benchmarks on SteamOS using Proton.
With the provided benchmark results, its notable that they are comparing the new ntsync to the Wine version that has no alternative. Results are impressive. But on SteamOS and Steam in general, we have Proton, not base Wine. And Proton has something else already implemented, that improves performance. Its not as good as ntsync, but my point is, comparing the new implementation in Proton won't be a huge difference like in the benchmark shown (as the benchmark is comparing Wine, not Proton).