What if you lose your phone? In my country banks only allow you to use one phone for mobile authorization, so you can't even have a backup phone. I really wish 3DSecure was optional so I can turn it of when going to foreign vacation.
My US bank requires SMS 2FA and SMS works for free because I am connected to Wifi. I have VoWiFi enabled. My US phone plan is with a budget carrier I only pay $15 a month for voice, sms, and data.
