Twitter has had two-factor security based on physical keys, like the Yubikey or Google's Titan keys, for a long time. You've been able to log in with said keys on your phone (assuming your key works with your phone) for a few months. But what if you have to manage your company's PR Twitter account while on the go? Or more typically, what if you have a USB-A key for your desktop and an NFC key for mobile usage?
In either case, the Twitter app for Android now supports logging into one or more accounts via multiple physical security keys, be they USB, Bluetooth, or NFC. Twitter announced the change via a tweet, naturally, and it appears to be live in the latest version of the app.
Secure your account (and that alt) with multiple security keys. Now you can enroll and log in with more than one physical key on both mobile and web.
And coming soon: the option to add and use security keys as your only authentication method, without any other methods turned on.
— Twitter Support (@TwitterSupport) March 15, 2021
At the moment you still need to log in with your Twitter password, but Twitter said that soon you'll have the ability to log in with only a security key enabled. Which is, you know, just one-factor security, but it's probably more secure than the same password you've used on two dozen other services.