No problemo! :)

The short answer is that when our posts payout, any portion in Steem Dollars are given as if 1 Steem Dollar = $1 US dollar. However, for a while now, these are really worth and sold on the market for a bit over $2 US right now. So, on the half of the author reward you would get in Steem Dollars (with 50/50 rewards set), you'd literally be getting paid twice as much. (i.e. the current $2 US price for SBD compared to the $1 US it's paid out as.)

You can still exchange all your Steem Dollars for Steem, which you can then power up. So in the end, with 50/50 rewards, you could still choose to power it all up...you'd just have more to power up.

I hope I didn't make it more confusing.