Security is at constant war with convenience. The stronger the passwords we use to keep our data safe, the more steps we take to lock down what we own, the less accessible our data and our devices become -- even to us. Balancing it all can be tough, and a lot depends on what the platforms and services we use do to help us. And nowhere is this more evident than mobile.
Multitouch keyboards, in large part, rely on things like like character pair prediction and auto-correct to make entry acceptable. Neither of those things are possible with passwords, and strong passwords require far higher than normal frequencies of shifting between upper and lower case, and between letters and numbers and symbols. It's the worst possible experience.