I was trying to decide on whether I should get the BSM on my MDX for the same reason. I had a Ford Windstar, which had real wide side moldings. I had received many dings on my car, so the moldings do not eliminate the dings, just some.
I think there are some dings that the BSM on the MDX will protect, and some it wont. It will just depend on the car next to you. I decided to skip the moldings and just try to watch where I park. If I do get dings, I know that I had all dings on my Windstar removed by one of the dingmaster people with no trace left at all, and without any painting. So if I do get a ding on my MDX, its not the end of the world.
The reasons I personally decided to skip the BSM, which originally I planned to get, was because of worrying that it may come off some day in the future, and how they look like an add-on rather than designed for the car. Most cars with side moldings have recesses for them, so they look like they belonged there. But I really could have gone the other way. My son actually talked me out of it.