OP you're describing something similar to bitcoin futures contracts.
Bitcoin futures: What are they and how do they work?The world of bitcoin – and by extension, the world of cryptocurrency – has been given a lift by the US Securities and Exchange Commission (SEC) recently giving its seal of approval to allow a new bitcoin futures contract exchange-traded fund (ETF) to start trading.
But what are bitcoin futures contracts, and how will this affect the price of bitcoin? Let us explain.
Bitcoin futures contracts explainedA futures contract is an agreement to carry out a transaction at some point in the future at a price that is agreed today.
In other words, if the value of something goes up before the sale is completed, then the person buying the item – whether it a fiat currency, stocks, commodities or, in this case, a cryptocurrency – gets a good deal. If the price goes down, however, then the person selling the item gets the better end of the bargain.
https://currency.com/bitcoin-futures BTC futures contracts can trade with 100x leverage in addition to the other benefits mentioned. Making them a boon for savvy traders and a massive liability for everyone else.
The way you describe "bitcoin bonds" is closer to put and call options trading than treasury bond markets, if I remember correctly.
I think crypto futures ETFs are legal in the united states. Wheras spot based crypto ETFs are not.