Yubikeys generally have much worse recovery scenarios than passkeys do, for consumers. In enterprise if you lose your yubikey, an IT admin can help you get back into your account. If you lose a security key as a consumer, you're generally in a much tougher account recovery situation.
You need extra backup keys in a safe place. They don’t explain that well.
Not all services let you enroll multiple keys. Amazon, with all the money in the world, was guilty of this for a long time.
Practically, it is a huge challenge. I would want my day to day fob, an onsite backup, and an offsite backup. That’s a lot of hassle and potential for mistakes. To even register the offsite backup means I need access to it. Remotely copying a password database is so much reliable
If you use a security key only for the most important accounts like Apple or Google, keys are set up once and then unchanged for years.