You certainly have point. I don't know why other people wear gen straps on their Pateks, or on any other reps. However, for me, wearing gen straps on it makes the watch special for me and among all watches in my collection. For me it is less about the physical attributes of the wear but mostly the mental advantage it gives me over the rep strap - it turns my 3K Aquanaut into a franken at a much more reasonable price than does a gen dial or a set of gen hands. It enables me to enjoy daily a genuine piece of Patek product.
In addition, I take care of most my watches and dont take them to swim at all - the one I take to swim would be my GS diver. Although all rubber straps are subjected to wear and these gen Aquanaut straps are no exception, taking really good care of them may prolong their usage so that I can put them onto future iterations of the Aquanaut as well.
Thanks