Switchable hubs have been around a while I think but they're not that common and I think they were considered unreliable (or less reliable) due to the extra bits and pieces needed to make them work. It's only ~1W off and 6W on anyway for their normal hubs.
Yeah pretty useless for most people, I just figured you guys who ride for many hours a day on dyno hubs not in use, it may be worth it. Marginal gains init. Otherwise you're just touring ;)
Switchable hubs have been around a while I think but they're not that common and I think they were considered unreliable (or less reliable) due to the extra bits and pieces needed to make them work. It's only ~1W off and 6W on anyway for their normal hubs.