You earn interest on your Steem holdings.

So many folks here don’t realize this. As far as I’ve been able to determine, the rate of interest doesn’t seem to be posted anywhere. The nominal rate is about 1.4% per year but the effective rate is more like 1.9% but fluctuates constantly.

A few months ago I crunched the numbers and did a post about it. Worth a look for anyone who wants to have a better understanding of how much interest you earn on your SP:
https://steemit.com/steemit/@preparedwombat/how-much-interest-does-your-steem-power-earn-i-finally-figure-it-out

(upvoted for visibility)