You are absolutely right that difficulty is the main obstacle to adoption.
OpenDime is an interesting system, it's not as multi-use as I'd like and I'd question whether it is as secure as it appears. Certainly, it's not as secure as I'd like. Having said that, it looks extremely efficient and effective at what it does do. If I was to use a disposable system that was an equivalent of a cheque or a traveller's cheque (and I used to use both extensively, it's only since I came to the US, where there was no cheque guarantee card and a whole host of restrictions on who accepted them that I've essentially stopped using both) then OpenDime looks like the system I'd use.
Yes, it is a matter of doing. What I have in mind is a lot more powerful than OpenDime and necessarily a lot more secure, but built from a similar premise of off-grid transactions.
When it comes to doing, I plan to be doing quite a bit on security (I'm working on a secure network appliance at the moment) but I point you to Plato's Republic where he says the wealthy don't bother to work well and the poor can't afford to. The same is true today, only the market is now exceedingly complex. "Poor", in the sense Plato meant, doesn't refer to absolute money but to the relative amount needed to enter a given market. The barriers are often higher than one would like.
Yes, making security something that's everyday and below the conscious level (it just works) was one of the original goals of IPv6, until certain agencies ripped that out. Making it "just there" for everyone is still doable, but unless you want to go one service at a time, it's going to require a degree of cunning. It can be done, though.