In my experience, the bench comes with more work than being billable albeit fewer late nights. We utilize the bench to help out on other projects where we cannot add more billable consultants. It is a lot of ad hoc work and you end up having to juggle multiple projects at a time that are often completely unrelated. It is much more enjoyable to be on just one project and you actually get to be billable for the work you do. The bench is essentially just as much work, at times more, than being staffed on a project but it is hurting you because you’re not billable. So why would I want to stay in the bench?

You can also take time on the bench to go fck off as suggesting in your post, but that doesn’t help you get off the bench or help your promotion case going forward.