Personally, If I read "memory leak", I expect c-style "lost all pointers to allocated memory" problems. If I read "space leak", I expect haskell-style "built up

Personally, If I read "memory leak", I expect c-style "lost all pointers to allocated memory" problems. If I read "space leak", I expect haskell-style "built up way too many thunks", like this. While the end results are similar, the mechanisms are wildly different, and just because _you_ don't differentiate between them doesn't mean that other people can't, or that it's not a useful distinction.