Comment by heleninboodler

The reason we use qwerty on a smartphone is extremely straightforward: people tend to know where to look for the keys already, so it's easy to adopt to even though it's not "efficient". We know it better than we know the positions of letters in the alphabet. You can easily see the difference if you're ever presented with an onscreen keyboard that's in alphabetical order instead of qwerty (TVs do this a lot, for some reason, and it's a different physical input method but alpha order really does make you have to stop and hunt). It slows you down quite a bit.