They take zero effort to setup, since it just adds to your existing phone bill. Unlike bitcoin, where people need to install apps, navigate subscribing to financial-like systems they don't really understand. The conversion rate will be tiny, and very few people who consider paying with Bitcoin will complete the process and actually be in a position to scan the QR code and hit the button. None of the other crypto currencies are even on the public's radar, and won't be unless Visa or Mastercard join in.