I also was trying to figure out why I would use this over Bazel. Then I remember reading a story yesterday about how ex-googlers miss their tooling when they leave. Their CTO is an ex-googler, so maybe this is the reason.
I'm not suggesting Bazel is perfect: I think e.g. Starlark's insistence on being a separate language does more harm than good. (FWIW I also think the JVM objection is a little silly.) But I am saying preferring the Google tooling would ostensibly mean you like Bazel a lot already :)
I think the term DSL is overloaded here? Consider all the Lisp and Ruby stuff that's definitely DSL but doesn't need most of a language implementation.