Had someone creating a Nima rest api, it was using JAX-B generated classes for request/response types ... and those used java.util.Calendar [and also no setters for the collections]. So there wasn't a relatively quick/easy way to turn off the use of avaje-jsonb in the generated code and just use Jackson [apart from removing avaje-jsonb entirely from the classpath].

So this is there to support that type of case, where someone hits some issue and just wants to "downgrade" to using Jackson [perhaps temporarily until any issue with avaje-jsonb is sorted].