what i am waiting to see which would help mass adoption
although it may have its cons
is simply BTC printed out on a receipt
with a wallet/pos system
just be paper wallets you carry
printed off a printer at checkout

a lot of people would understand BTC much quicker if they could touch it and see it
just print off paper wallet for their btc
to spend it just gets scanned and transferred to checkout
which then just prints off a fresh paper wallet with the change

obviously you could also then put straight on phone wallet
but printables would be good option at checkout for shops

shops could also help promote bitcoin by offering change in btc for first timers
with instructions printed on receipt too