Thanks for your great post. With all the questions we get about Steem Power, more people clearly need to understand it well and be able to make the right decisions!
Regarding the 10% "interest": I used the word "effectively" in my article, meaning that the extra money is not literally interest but can be seen that way. The extra money paid to Steem Power holders is meant to combat dilution of their relative share. As I understand it, both Steem Power and Steem Dollars confer this benefit, while Steem holders are subject to dilution (which is why you want to sell your Steem soon or Power Up).
Thanks for your reply! I almost feel like I should put a disclaimer of "I am not a financial advisor" on a post like this! I think my point, and your point too, is that people need to really understand all the angles when it comes to making decisions on their newly acquired digital assets.
I still think that Steem Power will Decrease by almost 10%, all other things being equal, due to the 100% yearly creation of Steem, since only 90% of that Steem comes back to Steem Power holders as additional Steem Power. See Dan's comments today here, for the complete explanation: https://steemit.com/steemit/@maniac/steemit-what-am-i-missing#@dantheman/re-dantheman-re-maniac-steemit-what-am-i-missing-20160713t214911691z