I don't think so. Someone who can use a keypad may have the manual dexterity to use a smartphone, but not necessarily be comfortable using a smartphone for this

I don't think so. Someone who can use a keypad may have the manual dexterity to use a smartphone, but not necessarily be comfortable using a smartphone for this purpose. I have known people who are comfortable with pressing buttons on an old flip phone, but simply do not get how to use a smartphone. Grasping technology is about more than just manual dexterity.