I'd argue it is, though, especially as people aren't born with the inherent ability to solve problems that cause pain, it acts as a good rudimentary indication that damage is being done. And even grown people, intelligent people in fact, might be more prone to doing things they know are bad for them if they aren't given pain feedback.

It might not be a perfect system, but the existence of unpleasant feedback is necessary when there isn't inherent knowledge of the inner workings of the body. And in regards to low-information, that doesn't make it unnecessary, just inefficient, but it's still allowed humans to diagnose problems for ages. It tells you where the problem is, and what intensity it is.

Saying that pain can be improved upon doesn't make it unnecessary.