Personally, Being a stillwater guy,
I don't give a crap what he says. I tie flies with ribbing over the shellback, and do just fine. I catch plenty of fish with them and they don't fall apart.

Besides, if they fall apart without the ribbing over the wingcase, that means people buy more of them, which means that he gets more $$$.
I think it's overrated.

Thats my (strong) opinion and I'm stickin to it.