A very small percentage of OLers do deadlifts, and a very small percentage of OL coaches recomend them. OL training seems to make yoru pull stronger even without them...
Just a little personal experience, when I was still powerlifting, my best deadlift was 707lbs. It was always my worst lift. When I started doing OL, of course I quit deadlifting. About 2 years into it, I went back home for the weekend once and had to make do training in the old YMCA on saturday. No bumpers and they didnt allow dropping, so I couldnt clean. Decided to fool around with some stiff legged deadlifts. Ended up doing 705lbs for 5 reps. So 2 years of no deadlifting, and I did my old one rep max for a set of 5!!! and stiff legged to boot.
I have seen similar things happen to other people who are not great natural pullers.