My assessment matches yours, very few online account login systems support U2F. Heck, many don't even support using a TOTP or SMS second factor. But the real

My assessment matches yours, very few online account login systems support U2F. Heck, many don't even support using a TOTP or SMS second factor. But the real value is for the most critical logins, such as to Google, or similar, where a breach would be tremendously harmful to you.