Do you use tablet to edit photoshop?
I do use one, I wouldn't say everyone does. I happen to own one because I am a graphic designer as well as a hobby photographer so I'd own one anyway for my profession. I don't think it is necessary. But it is a nice tool. Like any tool, it can make your job easier and more enjoyable. But no - it isn't necessary.
The Wacom Intuos series is what most professionals use.