Belly band after C section?

I am seeing every where that people are using belly bands after delivering. They are helping women get down to pre pregnancy size and I’ve heard for c sections they help with recovery. Especially when you cough or sneeze so you don’t feel like you’re going to come apart. They just look so uncomfortable. Like wearing a corset. Do you have to sit completely straight? Aren’t they cutting into you? Can you move around like normal? I’m curious to how they helped PP and especially how they helped moms recover from c sections.