RE: Everlasting STEEM Power; Why you should Power Up!

It might be strange to you...
but I still have no idea what "Powering Up" even means.
Is it commenting? Posting? Upvoting? Is it buying STEEM?

What are "Curation Rewards"?
I have zero. How do you get them? Do you want/need them?

I have 0.000 Steem,
3.333 Steem Power,
$0.122 Steem Dollars,
and $5.06 Estimated Account Value.

... What does that mean?
Do the dollars relate to the Steem?
Was one converted to the other?
Does one go down when I upvote?
How is account value determined?
When would I be able to cashout?

I'm not even going to ask about HOW I would cashout yet...
I've seen some posts where people do it, and it's confusing as hell to me.
I know people use Bitcoin, but I haven't been able to get my head around it.
I just know that Bitcoin is fundamental and important, philosophically speaking. I've never been able to use it like I use Paypal.