If Bitcoin replaces fiat and people eventually get paid in Bitcoin
Bitcoin cannot simultaneously function as a currency/money and as an asset/store of value. It theoretically
can function as the latter, but as a deflationary asset with a built-in production limit of 21 million, it is inadequate for serving the monetary needs of a modern economy. There is no reasonable mechanism for lending and borrowing Bitcoin, and further, the 21 million cap means that any sort of lending at interest is
impossible in a Bitcoin monetary system, because the fixed supply necessitates that the interest accrued on the loan must be directly taken out of the fixed supply of Bitcoin.
You all like to decry the nature of fiat as being "backed by nothing" or "money created out of thin air", but these criticisms are shallow. The operation of fiat is actually quite elegant and sophisticated, because in practice fiat currencies actually end up being backed
by labor and investment. When loans are issued (meaning, when new money is created) they are issued with some productive economic purpose in mind, and the borrower must engage in some sort of productive economic activity in order to repay both the loan and the interest due. This economic activity, in broad sum across the entire economy, is the foundation of real wealth creation. And this is why fiat is so effective at growing economies versus hard money, and why every economy in the world uses fiat and not gold (or Bitcoin) as a currency.
This is simply not possible in a Bitcoin system because borrowing and interest repayment is impossible. In a theoretical Bitcoin monetary system, all wealth would very quickly flow toward those who already hold the most Bitcoin and lend it out. Because of Bitcoin's fixed supply, all excess Bitcoin would necessarily be sucked up to pay the interest demanded by the lenders. It's simply not a workable monetary system.