I'm kind of curious why some bikes have different cable housing setups than others. Like on my newer road bike, the housing for the rear brake cable is segmented into two parts and goes from my lever to the front part of my top tube, goes bare, and then has another piece of housing from the end of the top tube and into the rear brake. On an older touring bike I have the cable housing for the brake is all enclosed. And I've seen other fancy schmancy bikes with internal routing.
So what's the fuss with all these different types of routing methods? Does any particular method provide any advantages or disadvantages? I'd imagine that fully enclosed housing provides the best protection along with internal routing.
I guess the reason why I'm asking these questions is because on my new road bike I'd like to just install fully enclosed housing for my brakes since they offer much better protection than having segmented housing with bare cable showing. If there are really no performance disadvantages to this other than cosmetic and the tiny additional weight of the housing I'd just like to have the best protection. I know on my bike I can't really do anything about the shift cable housing, but I'd like to do something about my brake cable housing.
What do y'all think?