The first sentence of the documentation already says it: "turn any set of notes into a powerful database". It's really just that, basically. It's a database-view, where the vault is the database and the rows are your files. There is a fancy GUI for creating views, and it seems there is the ability for live-editing data from within the view. Basically a more user-friendly replacement for the very popular dataview-plugin.
Maybe it's a bit harder to understand, as it's a more mushy than the usual relational database.
Maybe it's a bit harder to understand, as it's a more mushy than the usual relational database.