wen blockstream green support Hardware key like yubico for 2FA? in addition to the crappy SMS, Email, Phone call verification to avoid sim swapping attack?  why not offer the most secure way of securing funds to bitcoiners? 

 Use authenticator app or even a  @Blockstream Jade for your 2FA. 

https://help.blockstream.com/hc/en-us/articles/20182747993625-Use-Jade-as-a-2FA-authentication-device