Cameras in the house - why?

This is a rhetorical question. I know why (in theory) some HOs use them, but curious to hear personal experiences and perspectives.

I’m a sitter with over 30 sits completed. I rarely encountered cams in the houses (that I am aware of) but i often wonder if there are any hidden cameras around the house.

Question to all HOs out there why do you have them? Do you watch them, check the sitter/pet?