It would be hard to explain it better than this: https://forums.flightsimulator.com/t/wmr-scaling-and-dev-tools-some-explanations/339477?. The tradeoff between inside and outside clarity is quite interesting. And the explanations as to why are pretty technical.
Given how easy it is to switch settings without restarting MSFS, I will use a high WMR scaling (150-200%) and low TAA (50%) when sightseeing in a piston single, and 100% TAA and 50% WMR in airliners so the text is clearer. I continue to play with the other settings depending on what I’m up to. Clouds hit FPS hard, but are very pretty (as we all know). This: VR Bang-For-Buck Performance Guide - Virtual Reality (VR) / Hardware & Performance - Microsoft Flight Simulator Forums gives a nice break down of the general impact of the various other settings. Not all of which I experience to the same degree as he does. WMR and TAA settings for me have by far the biggest impact on performance and quality.
The same concepts are applicable to SteamVR, but I had noticeably worse performance when I tried it; it seems there are some known issues with current NVidia drivers and latest SteamVR client. Others are reporting better luck. It’s quite a moving target!