Are tire inserts like Cushcore and Tannus really required for most riders, or just people racing? Are they just a placebo effect, making people think they're better at damping? Anyone tried inserts and went back to just DD or DH like carcass tire? I'm guessing the cons would be weight and increase rolling resistance, any others? Seems like lots of people are convinced inserts are the way to go. I bike the North Shore (BC), lots of climbing and steep descents.