Two factor authentication via text message

Why is email the only option for two factor authentication. Every other service I am familiar with offers the option of text message or email. Text messaging would be more convenient.I understand the need for two factor authentication for logging onto a site that requires security such as a security system portal, a bank and so forth. But why is two factor necessary to login to the Ring store or this forum? Just now, I not only had to do two factor authentication to log into this forum, but while logged into here, I had to go through all that again to get into my store account. Add to that the further inconvenience of email over text authentication. This seems like overkill to me. This along with the lacking capabilities associated with Modes has led me to believe that Ring has not really thought things through very well.