If the medical bills are 30k and I get 30k settlement, and the medical bills get subtracted, what exactly is the point of a bodily injury settlement then?

In most cases when one parties policy limits are exhausted, then your own UIM will kick in. There are many factors that I am not privy to here. Such as, how many parties were involved, how many policies are available, what their limits are, what injuries are involved and more. This is a good lesson for next time. Get an attorney. Good luck.