From an enthusiast standpoint, I would love to have all my bikes running a 135 rear spacing. Having my wheels all interchangeable (and not worried about rim width) would be great for me. I would love having a bullet proof set of wheels for my rooad bike fitting my cross bike so if a friend visits I have two worthy bikes for a road ride. Also, would love to throw my cross wheels on my MTB for more efficient urban fun.
Yes, Sarah Outen's bike has a Magura HRB system. I replaced the hoses as they were both trashed after her trip from France to Tokyo. They did not perform well in Sakhalin mud. Discs would be better.The German company Magura has developed an hydraulic rim brake system against the trend.