Actually, Postgres does not add any performance features to point releases at all. Point releases are only for bug fixes. You may be thinking of MySQL.
Occasionally, there are cases that could be argued to be exceptions to the general rule. But that's a hard argument to make -- everything committed to a back branch is officially a bug fix. Things like optimizer regression fixes are "performance enhancements" in a certain sense, but are nevertheless justified as bug fixes.
I've reopened your comment upthread for editing. Please don't post off topic complaints like this though. The guidelines ask you not to go on about downvotes and also not to use allcaps for emphasis.