Because the line cuts through the water more efficiently due to its thin diameter, there is less drag due to water resistance, and therefore when bar fishing, the currently doesnt push your terminal gear as much and therefore you need less weight to keep it in place which is a good thing when playing a fish with less weight swing around. As for the part about doing a number on your rod and guides, braided lines have a tendency to wear your guides more readily. If you cast and somehow have the braided line wrapped around your rod, it can actually score the rod which is not great for your rod, especially if it is an expensive one like a sage or a GLoomis. Personally I like the braid when bottom bouncing because you can feel every little bit of the river bottom and the hit is much more amplified because as I said, there is no stretch.