When I select a page, I can set up Slack Notifications for that page. I'd used pages for the purpose of being a "folder" -- I'd just add a Child pages widget and call it done. In some cases, I'd set up a Slack notification if a page was added.
I was excited to turn these pages into Folders, but since we've had that ability there hasn't been the ability to set up Slack notifications if a page was added. This is the only factor blocking me from turning the rest of my fake-folder-pages into full-fledged folders.
Since folders don't have anything of their own to display when you select them, I expect it would have to go in their menu?