> The blockchain is huge This is only an issue if you're running a full-node. If you want to place limited trust in others, you can use a light client (like El

> The blockchain is huge This is only an issue if you're running a full-node. If you want to place limited trust in others, you can use a light client (like Electrum or blockchain.info), which are very easy to set up. > There is still no easy integration method with extant payment systems Coinbase and Bitpay are making huge strides in this area, so I don't agree with you that "no one has done it". > The system of block verification makes it impossible to do truly instantaneous transfers. This is a big one. Double-spend attacks are real, and people want their transactions to go through immediately. The legacy financial system takes upwards of 30 days for a transaction to truly be settled. The fact that bitcoin transactions can be provably non-reversible after just 1 hour is an enormous technological leap. > The system is vulnerable to 51%+ attacks 51% attacks will only get more expensive as time goes on. Also, in the event of an attack, there are strategies [1] that can be employed to minimize their impact. > Mining is prohibitively difficult for the layman. I don't think this matters for wide-spread acceptance. Most people don't mine for gold, but they still happily use it as a medium of exchange. [1]: http://gavintech.blogspot.com/2012/05/neutralizing-51-attack.html