There's no reason it has to hurt UX in theory. The difficulty is just in spending a lot of extra time perfecting the animations and interactions, which is 100% doable. We just released navigation present and dismiss animations a few weeks ago, which feel pretty great imo. They're non-interactive, and again, this will take a lot of extra work you get for free with native, but the tradeoff is worth it for us, and again, amenable.
Eh, these are easy fixes. We're making progress daily on making it feel more "native" (i.e recently added present/dismiss animations). Try the demo[0] in your mobile browser, should feel pretty smooth. We've tested extensively on a whole range on devices and performance wasn't an issue. It's really the animations (or lack thereof) that make or break perception of "jankiness." What we have now is our first solid functionality-oriented release; next releases focus on tidying up the edges.
Completely rewired how I view language, consciousness, and matter.
https://en.wikipedia.org/wiki/The_Matter_with_Things