I hope it won't be a Gish gallop. It indicates that there probably is not one single big case against Bitcoin but many small cases. There is an interesting essay about that here: http://www.gwern.net/Bitcoin%20is%20Worse%20is%20Better
+ I can certainly appreciate the opinion that Bitcoin won't survive in its present form, but I think it's becoming more and more obvious that cryptocurrency in general won't be leaving us any time soon, and I think ignoring Bitcoin's role in that development is extremely foolish.
I still don't understand how bitcoin will ever overcome that obstacle for casual transactions (as opposed to ones in which a 30 minute delay isn't a problem)
A valid transaction which is widely seen in the network will be part of the blockchain with a high degree of certainty, even if it is just a few seconds old. That is not perfect, but the risk of accepting unverified transactions with low volume is very low.
It is important to remember that most systems that we use today have serious flaws, including payment systems like credit cards and cash. Bitcoin doesn't have to be perfect in order to succeed.
If someone could come up with a response to that single flaw, I think most of the others (increasing transactions per second, size of the block chain, etc...) can be overcome.
How likely a credit card chargeback?
My understanding is that if you don't wait for multiple confirmations, then it's not particularly challenging to double spend bitcoins. That's why vendors don't accept a transaction as "good" until multiple transactions have occurred.
And waiting for 30 minutes to pay your restaurant bill would kind of suck.
That's incorrect, there is a significant cost associated with executing a double-spend attack. For small transactions, it's uneconomical to mine an alternate chain in order to execute a double-spend attack.
If you trust the miner a little bit, you can assume that a zero-confirmation transaction be part of the common blockchain. Now it's not advisable to do that when selling somebody a Ferrari and letting them drive off, but it's probably less risky than accepting a credit card payment.
Regarding reputation: I don't quite understand the point. You'd just have to sign your tx with a private key that has a corresponding public key with some reputation attached to it. This is pretty independent of bitcoin itself. You could even build a system where you deposit some amount with a third party (or multiple third parties using a MULTISIG tx), which will reimburse the vendor with that amount if a double spend is executed.
But I think your system would work as well - but it then needs more than just a bitcoin transaction from my wallet.
I'm just trying to think of how we can encourage Restaurants and Grocery stores to start accepting BTC, without getting scammed by double-spends.