What I like about paused squats is that you take the stretch reflex out of the equation so the muscles themselves are responsible for more strength production and they stay loaded for longer. So yeah they can be used to build strength and size.
What I like to do is 3-4 sets of paused squats prior to doing regular squats. Normally you can use 5-10% less on paused squats. So you could do something like:
Sets 1-3: 315lbs x 5 with a 2 sec pause
Sets 4-5: 330lbs x 5 no pause
Sets 6-7: 340lbs x 5 no pause