Does anyone use security keys, such as YubiKey? What do you use it for? U2F? PC login? Commit signing? Something else?
I've been thinking of getting one for myself, but I'm unsure of how much security they really add. My main concern is that my email is a single point of failure, but I can't use U2F with Thunderbird. If I don't plug that hole there's basically no point in using it to login to websites.