There exists a project where 99% from the code is PL/SQL, such as the front-end (Oracle forms). All 10 designers make use of the same DB instance for developement. The project is large (1000's of DB objects) so there's rarely any contention and then any which exist is serialized by securing objects in Subversion prior to making any changes for them in DB (this really is manual and never automated).

Wouldn't it seem sensible to make use of Git as well as other distributed VCS in cases like this?

My current ideas are that it wouldn't, as all changes affect other designers immediately, before they're commited in SVN.

My estimation isn't any.

I really like DVCSs due to it dynamic character: I'm able to do changes here, commit, there, commit, merge someone to another, make changes into it, commit, and just next finally merge new changes towards the “tunk” to ensure that other might find them and will also be impacted by them.

Inside your situation designers make use of the same DB instance for development. So any changes affect other even before the code is committed. And So I see no reason in making use of D (Distributed) options that come with VCS inside your situation.