You can make a page builder using it, but you're going to have to create content types for each block with many to many relationships to pages. It's not going to function like a WP page builder, but it also would allow you more control over what a client can add to a page.

Don't think there are live previews, but I might be wrong (people can create custom modules, like plugins, and I haven't checked in on it for a year or so).

One use case we made is a place where a non-tech savvy marketing manager at a chain of retail stores can enter/edit the store info & deals for each location. Then the info & deals then get updated on the stores' app, website, and on site displays from a single UI.