I'm surprised no one has answered this one.
There are a few theories on the reasons for the strange forward-facing barbs on the Friley points. One says that the barbs cause "extra damage" (i.e., bleeding) that makes the animal easier to track. Another says that the barbs are a "cultural thing" and are mainly artistic. There is also the possibility that there was a belief that points were "supposed" to be made this way and it was a superior design because reasons...
My take on this point is that since these points are so small, it really doesn't matter what shape they are. They will penetrate well all the same. So, why not make them look cool?