[dragontamer]

The problem with BTC is how long it takes to confirm a transaction. Paper-based transaction is instant, you hand bills over and you're done. Credit cards are the same.

BTCs take 4 or 5 block-chains before they're "confirmed", and you don't really know if your customer has "double-spent you" until the confirmation occurs. This makes BTC unacceptable to the vast majority of typical transactions.

Its fine for say... online shopping, because 30 minutes of confirmation time isn't that big of a deal. However, waiting 30, 40, or 50 minutes for confirmations is not the best way to buy coffee in the morning.

[vbuterin]

Most merchants in practice accept transactions immediately as soon as they receive the unconfirmed notification. The security is not 100% perfect that way, but it's still way better than the risk of getting a chargeback with a more traditional system.

[csomar]

It's probably instant for the 99%. I don't think people are willing to handle the security and technical aspect of Bitcoin. They'll hand these details to a service like Coinbase, which will have merchant APIs and accept transactions instantly.

[dragontamer]

http://blog.coinbase.com/post/43285532179/unconfirmed-transa...

In this case we fell far short of that goal (some transactions were delayed for a number of days), and for that I am truly sorry

Uhhh... you were saying? If you fail to understand the technical aspects of the technology you're building a business on, be ready for it to bite you in the ass in obscure ways.

Any implementation of Bitcoin will have "leaky abstractions".

[gojomo]

This theoretical problem isn't that big in practice. Ensuring your malicious second-spend 'wins' the confirmation race requires a lot more effort than an ill-gotten morning cup of coffee is worth.

If it actually started happening -- burning merchants who accept 0-confirmation transactions -- a bunch of cheap countermeasures could be adopted. For example, only accepting 0-confirmation transactions from certain origins with a traceable reputation, performance bond at trusted third party, or subject to other recourse/debt-collection. Or, having a consortium of major pools commit (for a tiny fee) that they haven't seen a competing transaction and will prefer the one presented first, by the merchant.