Sure, but that's the point: if Datomic is "the best thing Clojure's got" as far as killer-apps go—and it's not really that important to the community—then Clojure doesn't really have a killer app.

A killer app is something that looks like Rails does in Ruby, or Phoenix does in Elixir: a thing where 50%-or-more of the people learning the language are only learning it in the context of using that one framework, and so often get confused as to what's a feature of the language vs. a feature of the framework.

Which is, y'know, an awful annoyance for the people who use the language for other things—but boy does it pull people in.