Depends on the IGH. Nuvinci and Schlumpf definitely can. The efficiency (like all other marginal gains in cycling) is important for racers or long-distance to

Depends on the IGH. Nuvinci and Schlumpf definitely can. The efficiency (like all other marginal gains in cycling) is important for racers or long-distance tourers. For everyone else it needs to be considered against the maintenance burden required to maintain an exposed drivetrain which needs to be cleaned, lubricated and adjusted in order to maintain its relative efficiency. And weight...