One unintended benefit will likely be fewer vaccinated children.
If parents have to pay per doctor’s visit they will probably only bring their kids in if there is a problem. The doctors will tell them to bring kids in every few months for a check‐up, but those cost money. Those check‐ups are where doctors inject their multitudes of childhood vaccines. Without the vaccines children have stronger immune systems and don’t have common problems like ear infections, so they will rarely need to see a doctor unless they fall and break something.
No check‐ups means few vaccines. Few vaccines means less need for illness visits, which means even fewer vaccines.