[salient]

> but we're also pouring resources into building single-purpose chips that will be useless when bitcoin migrates to a different hashing algorithm.

I don't get this argument. Why do they have to be used for something else after "you're done with them"? You've made your profit with them (since if you aren't going to make a profit with them, you aren't going to buy them in the first place), so what else would you use them for?

The ASIC's serve a purpose: mining Bitcoin and maintaining the Bitcoin network. I don't get why there has to be "something else" they need to be useful for. Bitcoin is the point.

[ChristianMarks]

There is the opportunity cost and the social cost. And there is no canonical, singular "point" about mining that one could refer to that would obviate those questions. But maybe the social cost is low, e.g., many miners and Bitcoin speculators would otherwise have been unemployed, and would have contributed at least as much carbon to the Earth's carbon budget had they done something else.

[lukifer]

I see no reason to anticipate Bitcoin moving to a new hashing algo, given the investment in existing hardware, and that the hardware owners are the ones who vote with their gigahashes on how the network functions.

However, even if it were to change, there are several altcoins that use the same hashing algorithm (PeerCoin being the biggest), and/or someone will invent a new blockchain service to take advantage of the existing hardware. While I think there is great merit to ASIC-resistant hashing algorithms of ProtoShares/PrimeCoin/etc, that ASICs would ever become useless seems highly unlikely.

[dllthomas]

Attacks against cryptographic algorithms only get better. If SHA256 is weakened sufficiently, bitcoin (and altcoins that use SHA256) will need to move. Which it can, but that makes existing ASICs worthless.