I just copy this comment from @nanzo-scoop.
I BIG thanks to you @nanzo-scoop!
This is his comment about SBD @esanvicentem:
Steem Dollars is pegged to the US Dollar thus should be more "stable" than STEEM.

No matter how well or how badly STEEM does, you can always exchange 1 STEEM Dollar for 1 US Dollars worth of STEEM.

An additional attraction to STEEM Dollars is that it paying out interest at 10% pa.

STEEM Dollars are also liquid. You can cash out anytime. STEEM Power requires you to power down at a rate of 1/104 over two years (see here for a simple explanation).

That's a simple explanation of why people buy STEEM Dollars. A lot of bloggers, will like to cash out in a currency that they can translate to their day-to-day life simply. STEEM Dollars allows that.

Investing in STEEM is like buying a stake in the eco-system. As the network's wealth grows you share in the success. Also it gives voting influence.

For further inquiries:
Read this Quick Start Guide : https://steemit.com/welcome
And Steemit FAQ: https://steemit.com/faq.html
Good luck!