IMHO, they’re a great tool. As long as it’s pressure sensitive it should be good. Using a tablet is the best way to paint in Photoshop as it allows you make very realistic brush strokes.
Some tablets are simply pressure-sensitive, some will sense brush angles.
A pressure sensitive tablet is arguably a must-have tool, it unlocks a good part of Photoshop’s power.
Some people use a tablet exclusively, and do not use a mouse, in all apps and OS usage.
Vince