Because not everyone uses Linux?
This may be nail in Java's coffin if this plays out as implied.
It's nice to be able to install a JDK where you won't be charged oodles of dollars just because you accidentally used the wrong command line argument.
https://www.theregister.co.uk/2016/12/16/oracle_targets_java...
There's a XX:+UnlockCommercialFeatures switch which enables features like the Java Flight Recorder.
Other examples are the MSI Enterprise Installer and JRE Usage Tracking.