I know that 20-30ms is jarring because I've experimented in doing everything possible to reduce input latency while playing competitive shooters over the years, as has any serious FPS competitor. 20-30ms is highly jarring to many. Even playing SSB Ultimate over wifi on my Switch is super annoying for me to deal with.

Here's a recent HN thread on the revolution of compensating for network latency in QuakeWorld: https://news.ycombinator.com/item?id=19915698

You can simulate ~instantaneous input with this kind of approach, but not if the input has to travel to the server and back before it's registered locally.

Most people won't care about this, but it will certainly put a ceiling on serious people (e.g. streamers) trying to play popular, competitive games on Stadia.