Some Facts about Cambodia:
15 million people
18 million mobile subscribers
yes, 118% penetration! (multiple phones per user)
They can leapfrog the existing banking system.
David
My youngest wife in Kenya uses 3 cell phones. One receives calls for free, one makes phone calls for next to free, the other does text messages for basically free. She works in marketing doing cold sales calls and I know her boss helps pay for them.
When I was on the matatu (type of bus) into downtown Nairobi in the early morning, it was filled with young professionals. They were all playing with Androids and various tablets.
Most people don't realize how technology is leapfrogging in 3rd world countries. They are skipping the land lines. Phone and internet run off microtransactions. For instance, you can rent 3G Orange by the day. It is about 40 shillings ($.50) for about 3-6 MB/second download speed depending on the time of day. There are internet cafes everywhere for about $0.25 per hour.
Young professionals using these devices earn about $250 per month compared to typical salaries of less than $100 per month.
MPESA is already very popular in many African nations, but it is centralized, and governments keep raising the taxes on using it. I believe at some point this cause a huge shift to cryptocurrencies.