Just a simple what i think a solution is to the problem of secure, instant and somewhat decentralized transactions. this solution does not give the bs answer, just give all your money to some central authority.

This would rely heavily a non existent open source platform that has yet to be made.

the system would not be account based, but more email based. it would not require a brand new account name/password. just you supply your real name and email address in the website and everything else works through email where you need verification.

example:
i want to buy some stuff from walmart
i go to walmart.com and put my name "ctoon6" and my email "example@example.com"
walmart.com sends an email with a unique public bitcoin address that i send any amount of coins i want.
i send BTC5 to the public address
walmart sends another email back that is signed and says how many coins i sent along with a random pin number and password.
in the same email i get a link to an image to print out a card for use at the store. it would require the pin with the card, vaid for x amount of time
i could also get the card printed out at walmart if i wanted also. the card is only required at a storefront.
if i type my email address into walmart.com it would send an email of how many coins i have and my account information and such.
if i want my coins back i type in my email address at walmart.com and the amount i want back
they send an email and i click a link in the email that takes me to a page where i specify the public address.

in short, every store or company or site has their own account systems. this is better than a single, and pointless system where you have to trust 1 company with all your money that you want to spend versus a bunch of smaller ones where you would only loose at most like USD100 worth. this does not address the vending machine problem, unless every vending machine company formed a coalition or something.