You won’t know they are benign unless you plan on a biopsy or surgery for every finding. It’s exactly this reason why we only regularly scan people that have say, known cancer.
They'll know whether they're getting bigger or not. Pretty much the same for if you have a lump just under your skin that you can see and feel but this would allow you to see the ones further inside. So you just have to take the same attitude and advice towards them that a doctor would give you about the surface level lumps. What's the difference?