Here’s a little interview we did with the Mergify bot team to discuss how Cabal maintainers employ the merge bot on our GitHub repository:
tldr; several kinds of mundane tasks like rebases and backports become extremely easy because they require very little human intervention, so you are welcome to try it out too. In the text, we also mention a more sophisticated workflow implemented with the bot; namely, an automatic delay before the merge after all conditions are cleared – we use the delay to make sure most stakeholders had a chance to weigh in.
They (we) use Mergify and you can use it too! It’s trivial to set up, good enough, free. I don’t think there are any particular Haskell-specific caveats. I’d venture, the first time you don’t have to manually rebase somebody else’s PR already pays back for the whole setup effort.