Such bounties are indeed highly expected by bounty hunters. But to find a bounty like that is very difficult, even does not exist today. Like it or not we will still get paid with their original tokens.
the project side should understand, if in the future the value of their token decreases.
There are a lot of signature campaigns are running where participants get Bitcoin as payment. Normal bounty payment won't be in Bitcoin and Etheeum in most cases. Because those projects don't have enough funds to spend in bounties. They run the bounty campaign to attract investors, it means to collect money. In 2017, some projects paid through Ethereum like Crowdmachine project, my friends earned huge money at that time, But those projects are very rare now.