My understanding is that talc us an urban myth. It's a benign byproduct of the manufacturing, and at some point, cyclists thought that it's an improvement. I've never used it. Would I have fewer pinches if I used it? Well, that would be hard to measure, wouldn't it? I'd need to sample a whole lot of tube changes, with and without talc, and take a tally. In theory, if I know what I'm doing, I would never pinch a tube while installing it.