Well, people do need to reach you and people mostly aren't chained to their desks in an office any longer so you do need a phone of some sort. No, you don't need a tablet in general and I mostly never used one in a professional capacity.

If I didn't have a kid, I wouldn't have a phone at work. It would probably be off in my locker or something.

Children vs. adults…

Although many of us adults, myself included, could definitely use a strict break from the screens.