Personally I loathe stored procedures because often they include a lot of logic that shouldn't be on the database and they also generally involve SQL extenstions that are pretty terrible for the general-purpose computing you see them used for.

But if that layer is primarily used for providing, controlling, and optimizing access to the data I can see the appeal. And in that case? Being able to write the procedural parts in a language that's less-terrible than typical SQL extensions would be really nice.