Asking for a phone number as a verification method is particularly toxic for users such as myself who do a lot of international travel and essentially just use phones for data plans.

Due to a close call with one of my own accounts, I absolutely refuse to link a phone number to any online account, for fear of it being required months later when I'm in another country. I still nearly gotten bitten by this problem when Google wanted to use my old android phone itself as a secondary identification method. AFICT, the only safe solution is to also avoid using Android phones (or have no Google accounts you'd care about losing).