You used to be able to wipe the exposed portion down slide the housing over it, clean where the housing runs, lube it, make it hella fresh.Ooooh, you mean the old exposed cables that collect dirt and jam up the shifting. Yes, there is less resistance in those...until they jam up with dirt and screw up the shifting. So glad we are done with that and not having to change housing ever few months like back in the 1990s.
But im saying a hybrid of intetnal/exposed, use the frame as housing.