Has this idea progressed at all?
The idea I floated definitely has.
In Kenya, the largest note issued by their central bank is the 1,000 shilling (KES) note. That's worth about $12. Cash is still used widely for making purchases such as appliances, used cars, etc. Imagine going shopping for a new large screen TV and having to carry a 3" thick stack of bills.
Then imagine being the merchant, having to carry a satchel to transport the previous day's cash sales to the bank.
This idea has potential.