Why does traditional bond settlement have to be T+2? Frankly, it's not a technical bottleneck, but the three steps of reconciliation, risk control, and compliance that are unavoidable. You first need to confirm the funds are in place, then confirm the securities are in place, and finally verify both parties' identities and compliance. Going through each step sequentially, it can't be fast.

Dusk's approach is interesting. It handles these three steps in parallel, all integrated into zero-knowledge proofs:

The securities party uploads the position Merkle root to the off-chain custodian bank; the buyer maps euros into Dusk's native stablecoin D-EUR, bundled in batches via ZK-Rollup; nodes simultaneously verify three things — "Buyer has sufficient D-EUR"