So far my experience with this is that I have to dismiss it (the "hey you should try this!" popup) for every single repository that I view, really quite obnoxious.
This is brilliant from a release engineering/continuous integration perspective. Kudos to the folks who delivered this.
What if you still have too many pull requests per day, compared to the time it takes to run CI? For example if you get 10 PRs a day but CI takes 3 hours?
Not sure if this does the same thing, but bors[1], another implementation of this concept, will batch together multiple PRs into a single CI run and follow a git-bisect-like workflow to identify the bad PR if a batch fails.