Don't bother for primer, it'll stick better if it's a bit rough
are you taking the piss mate? primer should also be there to smooth everything out and coverup any little nicks etc. along with saying that primer filler is good stuff, just spray it on and its sort of like a thin liquid filler, just sand back and fulls in little holes/scratchs etc.
i think he means dont bother with the wet and dry before the primer
not to skip the primer altogether