To go mainstream a coin needs to be accepted in both east and west !
I do not agree entirely.
A coin needs to be generally accepted in a geo location, not only for online purchases, but also for in store purchases. On top of that, income needs to be in the same coin as well. ie a circular economy for the individual is required where income and expenses are in the same currency. OR, something needs to be done to the volatility of the coin against the mainstream local currency of the individual, ie when in a Euro dominated economy, the coin needs to be pegged to the Euro. The later is in my view required to make the step towards a virtual currency dominated economy.