BTC works because of PoW. Satoshi realized that consensus in a network could be achieved if the nodes committed computationallly to their version of the story. Using computational means to show how confident you are that you're speaking the truth prevents malicious nodes to influence the network with untruthful facts. But "computational" is too theoretical of a term. In reality, miners care, not about how many operations their calculations are taking, nor how long they're taking, but about how expensive the next block will be to mine. Really, miners use financial means to back up their version of the story. If their block is accepted by the network then the financial goods spent in the mining process are collected back with a profit; otherwise they're lost. Miners stake their financial goods to "prove their point".

Now, I guess many miners use traditional currency to buy all those nasty plastic high-tech gadgets that speed up their calculations. My two questions.

• Does this economically "link" in some way BTC to physical currencies?
• And more importantly. If the time comes that the traditional currencies are replaced by BTC, miners will spend BTC to buy their graphic cards and everything they need, so they'll actually stake BTC in order to prove their point. So in a fully bitcoinized economy, won't PoW be identical to proof-of-stake? Let's just obviate the immense pile of e-trash and the huge electricity consumption gap that separates both protocols in reality.

The title of this post should be "Will PoW converge to PoS?" but I liked a catchier version.