[Epitom3]

You still have to carry something right? How is that different from carrying your phone?

[ev1]

It's on a/your keychain, wallet, or backpack, where phones are difficult to fit. It doesn't need wifi, recharging, or a battery or mobile plan. Anywhere you need to use it will have some way to connect it, like checking your email in public, tapping it against a phone to log in, etc. It's orders of magnitude cheaper than a phone and you can have numerous backup keys in safe places if needed.

If stolen, has little to no resale value and zero personal information on it, and you can unregister the key from online services