[giantrobot]

For one no cryptocurrency is really designed to be used for actual payments. They all are deflationary by design so the future value of cyber bucks will be higher than today's value. If you spend cyber bucks today you're losing out on those future gains. It's irrational then to ever spend cyber bucks.

Unless cyber bucks are accepted to pay taxes in your jurisdiction (they're not) they need to be converted to a currency that is accepted. Thanks to the deflationary nature of cyber bucks, their conversion rates fluctuate wildly and constantly. The conversion rate can even change while waiting for a transaction to complete.

To boot every transaction is caveat emptor, there's no protections against fraud or even simple errors. Access to a wallet's private keys (even if they're not your keys) confers access to the wallet and all of its cyber bucks.

If the goal of cryptocurrency is to replace fiat currency transactions it's like the worst possible design for the task.

[Aerbil313]

Seriously, check out Monero.