Nokia's recently produced a couple of Dual-SIM phones which I haven't seen around much in Europe. When visiting the Philippines, however, I could observe them being marketed by the local Nokia stores alongside pretty much anything else in the Nokia portfolio, including the Nokia N9 and, as a major absentee, the Nokia Lumia.
While observing the people in a park in Makati, Manila's business district, I noticed that quite a number of people had at least two phones with them, some of them even three. When asking why, I was told that most people use on-net "all you can eat" packages while voice calls and SMS messages are rather expensive. So it seems to be cheaper to get a couple of prepaid SIMs from different networks and extra phones rather than to pay for inter-operator charges. So for people with a quite restrictive budget, a Nokia Dual-SIM phone probably makes a lot of sense.
People in the Makati district, however, probably have a significantly higher income than the average consumer in the country and I could observe that one of the two phones was usually a smartphone while the other was a what many people a low end phone. The smartphone was usually either an iPhone or a high end Samsung or HTC Android based device. I failed to see anyone using a Nokia smartphone.