how do you know that the one in spain isnt an equally rabid dog but just further away, and with the disadvantage that by the time you actually get to see it, then its too late cos youve paid and the seller has pretty much had plenty of time to sell it.
as for inboard disks, they were a solution to a problem that neednt have existed but for vanity.
bike disks live out in the open air and so corrode, but manufacturers dont want people to see their product with rusty bits exposed to view. so, in the 1970s when disks were becoming the norm for all bikes, they experimented with stainless steel and chrome plated disks. they looked great, they didnt rust, problem solved but for one tiny issue, they didnt work (chrome) and they didnt work in the rain (chrome and stainless) many bikes had chromed disks, iirc triumph and honda used them, most owners hated them till the chrome wore off by which time they were passable. bmw used stainless which were poor in the dry and awful to the extent of being dangerous in the wet. solution was to drill vent holes in the disks, thus allowing the pads to scrub the water away and grip the disk cos of the edges of the holes. they were still bad, but they werent quite as bad. (although the stainless disks would then crack between the holes due to stainless steel becoming more brittle when it got hot and the expansion due to brake heat meant that most drilled beemer disks either have cracks or will have cracks soon.
meanwhile over in italy they didnt really care about a light dusting of oxide, so they fitted cast iron disks to their bikes and they would stand on their nose wet or dry. soon enough metalurgy caught up and steel disks were formulated that wouldnt rust as readily as iron but werent entirely stainless. meanwhile the onboard ventilated disk was invented, oddly it used an iron disk which would have been fine out in the rain, but stuck inside the wheel the heat build up meant that many would crack in use and need replacing.
some wags in the bike press contended that the onboard ventilated disk was hondas way of recouping all the man hours its dealers lost fixing camchains in their v4's by adding another hour or 2 to every service due to the time it took to strip the brakes to check them.
personally, having a bsa in the shed, im well aware of the true meaning of crap brakes!