Hello @danielfs
To me it's always been a mystery how Steemit's economic system works. Generally one receives the STEEMs or SBDs from the posts we publish. But sometimes you only get STEEMs, sometimes SBDs along with SPs in common. I don't even know what percentage is assigned to each of you when you win at the end of the 7 days. And that's all I ever care.
I also had no idea that STEEM could be purchased outside the platform. There are few STEEMs exchanges.
I really forget that Steemit is not only a social network, it is also a blockchain, like Bitcoin or Ethereum.
There should be a simpler way to explain these things, whether with dolls or cartoons. 
But you've made me interested in the subject.
Thank you for sharing 