I have few Rolls Razor, I think they are a class of it is own, they are very well engineered and built and also they are very cool. So if you ever come across to a decent one(without rusty blade, cracked hone and dried out strop) and can afford it then buy it. Even if you don't use it, it is a great piece to look at on the display shelf. Even some women and other people not interested in shaving and vintage stuff loves it and asks questions about it.
When it comes to shaving; from my experience it gives a decent shave if only you spend a lot of time to hone it properly. I honed mine on a coticule, then 12K Naniwa and the shave was a good normal shave, nothing wonderful. I can get better shaves from a straight razor and a Gillette flair tip or slim twist/adjustable with fresh Astra or Gillette silver blue etc..
If you want a decent shave from a RR and decide to use the hone in the contraption only, then in my opinion you may find it bit uncomfortable(depends on the previous usage and the state of the blade as well) However in this forum we have some honemasters with plenty of good reputation and experience, they should hone the razor for you.
Finally why they are plenty and easy to come across and inexpensive? Because lots of them were produced, they were built to last so they still stand strong, they were widely available(all over the world), spare/repair parts were available as well, also they were common/popular Christmas/Birthday/Fathers Day etc.. presents.