We should enable merge queues, to ensure that main branch is always up-to-date in a PR branch. In busy environments, a PR can quickly drift out-of-sync from the main branch while it's being reviewed. Merge queues would allow us to auto-ff the branch to the required HEAD and prevent incompatible changes.
We could use other options like Bulldozer or Bors, but I consider merge queues more than enough for our usecase