One of the new features of Taproot Assets v0.4 are trustless on-chain swaps 💱 using Partially Signed Bitcoin Transactions (PSBTs).

With this feature users can swap assets for bitcoin or other Taproot Assets allowing non-interactive trade without requiring the trust of their counterparty or a centralized coordinator.

Example: Alice creates a PSBT that sends her Taproot Assets out and sends back to her a BTC amount. She posts that publicly. Bob can then come along whenever he likes, complete that PSBT, and broadcast it to the network effectively buying Alice's Assets in exchange for BTC.