I used to think the same, but I started using both sometime in October. It really looked much better for a marginal FPS cost, as other people reported (see https://forums.eagle.ru/showthread.php?p=3663577).
Maybe this is not the case anymore, I haven-t updated DCS since then.
So with this trick, no more AA needed since the 2.0 supersampling corresponds to PD 2.0, am I right?
And yeah using 1080ti, and Kegety's mod.