Rear brake of the Bimota: it does its job of aligning/steering ont he track and is almost impossible to lock up. So, lek the pegs, safety is the reason.
Folding pegs? AFAIK they are, like left shifting 1st gear up and lots of other nonsense, the result of Naderism (US legislation).
In the EU, there is no rule that pegs have to fold up. Once in a while, I have a dispute with the inspection guy (invariably one that doesn't know beans about bikes - "hugh - right shift? I won't test ride it" or how about, " rear brake doesn't work, the wheel won't lock up." or maybe, " front rotor is kaputt. " about a full-floating cast iron rotor).
Last one was last year:
http://cembalobill.blogspot.com/2008/05/german-mot.html if you haven't entertained yourself with that one already.
As for costs, the folding pegs are definitely far cheaper because they are die-cast and don't have to fit anything. Don't as a rule, either. The hinge brackets are stamped. The only "precision" part of the whole is the turned stub on which the pedal turns and that part is common to practically all bikes of a given make and then some. Witness the blacksmithed stuff on the MZ. Precision? As I mentioned elsewhere, the Yamaha brake pedal with bronze bushing fits as well and much better.
Friction stops. Most old racing twist grips have set screw and need it, too. In the days of jumpstarting the race, it was mandatory that the engine stopped when the grip was released. there was no idle set and indeed those racing carbs don't have much allowance for setting an idle. the Bimota has 40mm smooth bores with size 5 idle jets: infinitismally small, just there to plug the hole. Since you could not let go on the twist grip while standing, the set screw was necessary to set an idle in the paddock. Our Laverda has one and so does my Mondial. The Bimota does not and it can be a royal pain since it doesn't run below 3000rpm anyway.
Riding "the way your supposed to" according the the legislators that don't know how means basically plopping down on your ass, leaning back and toddling along at the max 65mph. (sounds like Easy Rider doesn't it? another of those very unfortunate...) Folding pegs don't matter there, that's for sure. They're just a place to put your feet. Running boards would be better. Ain't motorcycling tho. Never was either, except maybe in California and Nevada. They do matter if you are actually actively riding and using the pegs to displace your weight.
So anyway, practically all manufacturers, even Bimota, make hinged pegs because in the US they are mandatory.
Now you take your R6 or Ducati or Gixxer and buy a set of Gilles rearsets with ABE (vehicle authority approval) and mount them and that is entirely legal anywhere in the EU. Probably anywhere in the world outside of the US.
or these
or these from ABM
or these
or these from Lucas
etc etc etc. there are so many available for so many bikes, just not for the Skorpion and also not for the SZR.
Don't any of them fold up, however, and for good reason.