Even though you're technically wrong (the best kind of wrong), I can see where you're coming from. Even microcontroller ICs without enough memory to store this comment are real computers and are silent, but if you say you've built a silent computer and then unveil some Arduino contraption, expect eyes to roll.
That said, I still think smartphones qualify as computers even by your productivity definition. Newer smartphones would sit somewhere above older netbooks on a ranking of overall utility.
That said, I still think smartphones qualify as computers even by your productivity definition. Newer smartphones would sit somewhere above older netbooks on a ranking of overall utility.