I believe you are referring to Datomic's pull syntax (https://docs.datomic.com/on-prem/query/pull.html). The way I see it is that this is an add-on to the query language, not a core part of it, since it applies to the output of the query only. This would be analogous to having a GraphQL server on top of Cozo's relational model. (In fact, in earlier versions of Cozo we did have something like the pull syntax, but we quickly decided that we do not want two distinct ways of querying data in the same database, nor do we want to create a GraphQL clone).

I personally find Datomic's way of doing things a bit too convoluted, as you need to

- learn how to define the schema

- learn how to transact data

- learn how to query data

- learn how to "pull" data after the query is done

and the steps are all very different.