And Vanguard specifically only supports Chrome (last I checked), so it's a nonstarter if you primarily use Firefox, even though my Yubikey works fine on other sites with Firefox. Perhaps WebAuthn will fix that, but it's the current reality.
Instead of SMS, I wish more sites would fall back to email. There are a lot more scenarios IMO where I don't have access to my phone/SMS than not having access to email, and most email providers are better protected than SMS.
