OData is more or less SQL over HTTP. You get a rich toolbox for selection, projection and transformation of datasets exposed as an OData source (think EBay listings and SQL Server tables and reports), along with the remaining letters of CRUD.

Odata is à standardized rest use case for generaal purpose data access, so client tools can use it out of the box. Something like sql but over http. Some tools that provide odata support: tableau, tibco spotfire, linqpad, excel.

Excel is a nice example, you can have a sheet with data pulled in over odata from any app that supports odata.