Chivo wallet is as close to a CBDC as you get without it being on some blockchain or run by a third party.
Chivo wallet doesn't use the banking system. It is a walled garden monetary network. Additionally, the "dollars" in your Chivo balance may not actually be U.S. dollars in a bank account but a dollar-pegged stablecoin token.
Central banks might like that. So that's why they might be there.
If so, hopefully they learn that just like the eNaira CBDC in Nigeria, almost nobody actually needs nor wants to use a CBDC. And without people using it, it fails -- as it is expensive to build and operate.
But as far as this event being interesting ... don't you find it curious that it is mostly only the central banks from developing countries that are in attendance? It would not be surprising to find that the developing world central banks were the only ones invited.