Feedback is a good use case for custom issue types, though. We create feedback issues that are not actionable of themselves, but can be linked to tickets, so engineers get a feeling of what customers think.
There is the issue of dupes but it avoids the other issue, which is that if you hard decline too many requests from right after they are submitted, stakeholders may stop giving you feedback, which is a bad thing. So it is an unhappy middle ground (which is I feel the normal place which product management occupies. I could setup a small shop in the unhappy middle ground and sell souvenirs.)