Yes, "thumbs up, thumbs down" voting is a pretty good way to collect directionally unambiguous feedback that can easily be aggregated across many users to serve as training data.

But it's terrible interaction design for communicating what you want. Imagine trying to fulfill the 1001st most common user need and pressing "thumbs down" 1000 times until you finally get there.

In such cases, being able to construct a more specific prompt would save you a lot of time.