This would be a really big deal if it happens, essentially bringing Square Cash to the masses.

I can believe there is a market for this service, but that doesn't say much for the average consumer's savviness

Debit card numbers, designed to take money out of your account, are what fraudsters want and have compliance policies so strict even bank employees usually don't get access to the full string. Account details are less useful to fraudsters and generally printed all over communications from banks, including the checks and remittance advice handed to third parties.

So why would rational people prefer the latter, particularly if it involves paying a premium?

Is it another startup whose usefulness stems in a large part from the lack of ubiquitous free, same-day interbank payments between checking accounts in the US (unlike much of the rest of the developed world)?

What will the payout time be for it to hit the debit card? Is it instant? This is awesome by the way.

A couple of commercial services exist like this today. Repayonline.com and adaptivepayments.com have similar services. I believe one of them is the engine behind square cash. How will this be different, other than price and the open source angle? Will it be limited to the same contract negotiations bank-by-bank or network-by-network?

Should be lower friction for our users!

I'm probably not the first to think of this, but it'd be awesome to be able to sell bitcoin and have the fiat appear in your account instantly.

Could I push to my own debit card for budgeting purposes? e.g. push $500 every month

yes pleASE!~!!!!!!!

Nice nice nice! Let's remember that Balanced was also part of YC, along with Stripe. Not sure why the title was changed to remove that fact.