Building distributed applications that involve multiple organizations is hard with today’s technology. For each application, all organizations must agree on the data encoding, transport mechanisms, and interaction rules, and all must implement their part of the interaction correctly, including authentication and authorization. Once implemented, such an application often becomes a silo: there is no general convenient, secure and privacy-preserving way to integrate such applications and compose the business workflows that they automate.
The big problem is bootstrapping the network; as you say, setting up yet another format (DAML in this case) is a huge ask. But we're starting to see the beginnings of a network, as in the next couple of years the Australian [2] and north-bound (i.e., mainland China) Hong Kong securities [3] will be accessible through DAML.
[1]: https://canton.io [2]: https://www2.asx.com.au/markets/clearing-and-settlement-serv... [3]: https://www.ledgerinsights.com/hkex-daml-smart-contract-stoc...