Well, now one exchange did a great job as they released SMS verification as an option on 2FA. For me SMS codes are convenient for us traders. No hassle downloading app also Authenticator apps depend on a shared secret that both the app and the server need to store. This “seed” is combined with the time to generate the 2FA code. Anyone can crack the app or the server and recover the secret. Whereas SMS codes are just random values sent by the server, so there is no one who could predict the next code in sequence. I find this news here https://twitter.com/GenovesePierina/status/1064506032293068801