But there are UX issues with passkeys as well, that aren't all well addressed. My biggest gripe is that there is often no way to migrate from one passkey provider to another, though apparently there may be a standard for this in the works?
In fact, it’s not even meaningfully more secure than passkey (as passkey is designed) - passkey is, however, more convenient.
So it’s more ‘one weak factor + (really times) one medium/strong factor’ vs ‘one medium/strong factor’.
Which yes, the first one is better in every way from a security perspective. At least in isolation.
The tricky part is that passkeys for most users are way more convenient, meaning they’ll actually get used more, which means if adopted they’ll likely result in more actual security on average.
Yubikeys work well if you’re paying attention, have a security mindset, don’t lose them, etc. which good luck for your average user.
I don't think that's a reasonable assumption for most people, and you're screwed in that situation even if you use yubikeys.