Actually, Dzaima's APL app for Android has a very intuitive keyboard, coupled with APL's terseness, allows me to do pretty intricate stuff on my phone that I can pick up later at my desktop if it gets bigger. A lot of the resistance to the array languages is one of familiarity and aversion to anything new or different. Just try it. Math scared you as a kid too most likely, and even though you may not be a master mathematician in your adult life, I am sure you cleared some seemingly obtuse hurdles in your youth.
Honestly I think you'd have to be pretty proficient at APL for the touchscreen typing to become a problem. When I dabble in APL, I use the mouse to click on the buttons in the Dyalog language bar[0]. It doesn't matter -- it takes me much longer to think of what to type than it does to pick with the mouse.
That and finding the symbol on the the keyboard if it lacks the APL labels. I learned it with a small reference card I placed on top of a standard IBM PC keyboard.
