Silk road is generally helped by the presence of curse-givers more than your average strategy, because you can look to three-pile a lot more easily, and it's going to take much, much longer for your opponents who aren't SR to get to 8 provinces with all those curses floating around, whereas, yes, it takes a good deal longer to get to your SR and duchies/estates too, but not nearly as much longer.
However, SR isn't helped in this respect NEARLY as much as Gardens is.