Problem is rollback
With source code you can easily roll back to a previous revision. Once you break data, you're hosed. It's changing constantly, so you don't want to go back to last night's version. That's why the goal (in this context) of stored precedures is explicitly to make it harder for anyone to change how the application interacts with the DB. Worst case, a delete statement without a where.
So yes, you are just trusting a different group of developers. But hopefully the DBAs are more concerned with, and more trained in, maintaining the data than with adding features.
