A lot of people use it as a step up from Excel.

I’ve got quite a few scientists using it for data analysis, a whole bunch of people importing sales data for querying.

A good number of folks never write any SQL and just use the GUI to sort/filter data.

I’ve also heard from people who use Base to design a schema and then export the SQL into their codebase.

EDIT: I should add that Base does nothing that that the command line tool can't. But it does offer more convenience, particularly for those who might be less comfortable writing SQL.