Sounds like a shitcoin scam...

1) hand over your btc to the us government.

2) US government gives you 1:1 shitcoin in return (USABTC)

3) exchange your USABTC to USD

4) wow tax free as long as your shit stays within in their ecosystem...

Oh, you want your BTC back, even if you didnt do shit with it? Lemme hit you with a 20% tax. Extra bonus, your UTXOs are certainly kyc'd and flagged. See case 2...