[bdr]

As long as we're talking about Bitcoin, mind clarifying your criticisms?

it almost totally fails to achieve its security objectives, that it exploits a misperception about anonymity to handwave away the fact that for most users it is not anonymous

Are these the same -- both referring to the mere pseudonymity of addresses?

it is reliant on centralized infrastructure

How so? My understanding is that anyone can generate a new block, it's just (linearly) more likely to be you the more CPU you have.

and (most importantly) that it is meaningless as a currency

This seems like the weakest criticism. There are many conventions that work simply because they are conventions. In other words, they are self-supporting. Bitcoin has bootstrapped to the point where such a convention exists, and people are productively using it as a currency. This may not be the level of rigor you're used to in your work, but it seems plausible that a convention like Bitcoin could last for a significant period of time before collapsing.

[tptacek]

The dollar isn't a currency simply by convention. Neither is gold. It only seems that way in the frictionless vacuum of message board arguments.

[bdr]

Agreed, and I didn't say they were.