You may not realize this if you don't type a lot on your phone, but if you do, it's a huge difference. And if you don't type a lot on your phone, it's probably because you need a better keyboard.
And to clarify, SwiftKey is my keyboard of choice. Swype is a popular alternative, but I never got into sliding around the keyboard because I found it mentally fatiguing. The reason is because on SwfitKey I think about what I'm typing as words. With Swype, I have to think about each letter and where my finger is moving, and I end up forgetting what I was writing. Plus SwiftKey's prediction engine and interface is just much better and it's much easier to use taps one handed.
So you offer evidence that SwiftKey is minor consideration because it's not singled out in the referenced article, yet you agree with my first point about the importance of defaults and intents that are also not singled out in the referenced article.
I have a 5.5" phone that is pocketable and a 10" tablet as well. So we're in the same boat except my screen is bigger than the entirety of your phone.