1. No. It's not javascript only. https://old-search.marginalia.nu/ is still available. It is also mentioned in https://about.marginalia-search.com/article/redesign/ as gonna be there for a very long time.
2. I don't think just because it uses javascript make it bad. It's a very nice site now. I prefer it better than old version. My website doesn't use JS for any functionality yet. But I've never said never either. The reason hasn't arised that I need to use JS. The day it does, I will use it.
But I understand the sentiment though. I used to be a no js guy before. But I've been softened by the need to use it professionally only to think --- hmmm, not bad.