Some kudos due to Radigan here. Yes, the Stellar / IBM cooperation offers some potential. But there are many things this will not solve for. For example:

Risks: There is likely to be commercial bank risk; is the vehicle holding the collateral really bankruptcy remote from the company operating it? What is the commercial risk of the Operator?

Inter-operability: Will this interact with other protocols and software on other chains? Will it interact with a chain that has settlement in another currency or a securities settlement platform in another jurisdiction?

Finality: Does this offer finality of settlement? This is essential for any form of institutional settlement.

Liquidity: How quickly can you swap into out of this product vs fiat USD?

Governance: Who is in charge of the chain this operates on and who csan make decisions?

All very thorny issues.