Nr. 3 is very problematic for satellite connections, which have extremely high latency, making HTTPS websites unusable. I guess that is why Google went with plain HTTP in Africa.
This isn't only a consideration for Africa- I am in rural Missouri, USA, and I am stuck with a satellite connection. HTTPS sites are several times slower than their HTTP siblings. The problem, as I understand it, is that my service provider can't compress the pages before sending them over the satellite link.