In Gmail I can setup custom layout of multiple inboxes. I can e.g. show first 10 unread messages, first 10 email with given label, and the rest is shown below. Those lists of emails can be collapsed if needed.

It allows customization of what I can see at a glance when I enter my email and see what is important to me. I don't have to go through folders and labels manually.

Those inboxes also allow filters. I can setup an inbox that shows emails with applied label and that is unread. Or make rule to show inbox that has two different labels applied.