" while it played exactly the same music as could be heard from commercial stations on land. So it was not even musically unique. "

I've never understood the point in competing with legal pop music stations - They have far greater resources and facilities to do so and yes they obviously do make some money.
In all my years doing land based free radio I'm proud to say I've never played Kylie Minogue. When I heard that on Caroline 558 it was an instant 'Oh well, not listening to that anymore'.
The present day output is far more to my musical taste.
To me Caroline's USP is decent album music and long may it stay that way.