As a recent explorer of the Hive ecosystem, I've been noticing these tipping coins, but not really understanding how they worked.
That changed recently when I discovered 
In for a penny, in for a pound, so I picked up 100 $coffee on Hive Engine and started to tip posts I like with !COFFEE.
I have to say, I am enjoying this extra dimension to following content I like, it feels nice to be able to leave a token of appreciation and at the same time, I am rewarded with 0.05 Coffee, a truly symbiotic system.
P.S This is my first post, all advice appreciated