It would be a trust among communities, in contrast to the trust among persons that is the dominant model here in duniter. The (encointer) communities are formed by a protocol of regular real life meetings, so their trust is based on these meetings.
Encointer implemented a similar to the idea I was suggesting here in duniter since 2016, and you refused it.
Have a look at the current encointer communities, on which it is planned a community web of trust (similar to the persons’ web of trust you have here in duniter) to be created.
Encointer Explorer
I still believe that a web of trust among communities/assemblies scales much better than a web of trust among persons. So duniter is in the wrong path.