It really is not the case that dual SIM phones are largely limited to Europe. They are extremely popular in Africa, and as I understand it in India and China also.
There are quite a few reasons for this. In my case I can get a decent Internet connection from one provider, but cheap calls to friends and family, and better money transfer facilities from another. Other users my be tied to one provider for their work, but prefer another for their private life - usually on cost grounds. Yet others simply like to have dual personas. OK for non-smart phones, some people get along with carrying two small phones, but carrying two sizeable and expensive smart phones is a bit much, and if you get robbed or something you have more to lose.
It would be a pity if CM were restricted in the long term to techies etc who were not interested in such considerations.