The core libraries are used, for among other things, to parse flight recordings across Oracle AND OpenJDK versions, ranging back as far as Oracle JDK 8u40. These libraries are used at, for example Datadog, for parsing and processing/datamining recordings.
Here is an example (but not using maven central, but the Core API bundles published by AdoptOpenJDK in their own repo):
Recently New Relic asked in the AdoptOpenJDK slack if Adopt could publish them to Maven Central.
I propose that either Oracle builds and publishes the core bundles in a timely fashion on Maven Central, or shares access to the org.openjdk.jmc groupid with either AdoptOpenJDK or Red Hat - both have expressed an interest in helping out.