Seems like the leaderboard is only for subscribed members?

That's a shame. I was only playing to try at get top of the leaderboard.

If that's the case, I have been wasting my time. 

>Seems like the leaderboard is only for subscribed members?

This ^ is correct :)

Why not create an overall leaderboard then?

I was only playing to get on the leaderboard. If it is just for subscribers the interest goes.

>Why not create an overall leaderboard then?

Probably because subscriber money helps to keep the game 

free

 for those people who don't pay. Hence why they receive certain premium features (No ads, access to full rooms, score on leaderboard etc.)

If you really want to get on the leaderboard simply subscribe.

leader board doesnt really matter its about playing for fun and improving your skill at the game