Yes, there is a use-case for it. If you don't have triggers or transactional concerns on the table and you want users to be able to truncate tables while not allowing them to do things like change the table structure. I proposed a patch a while ago to implement a seperate permission for truncate but it was turned down because of concern over using the few remaining bits in the ACL structure.
I second this proposal My problem is that some users don't have access to change the structure but they wanted to delete all data from the table they try truncate - does not work because not the owner so they make a delete from a really big table So I would like to see a truncate permission - makes some things easier in my opinion -- Ewald Geschwinde http://www.postgresql.at
