The thing is that @promoted bot does not promise you to break even. Not at this time. Read here - my little test and here - the official announcement.
It doesn't have enough SP yet.
What is this service, or any other similar, good for is yet another question ...
Edited ...
You are testing lending of SP and I was testing upvoting. Sorry, my bad. Two different stories.
Still, it doesn't add up to enough of SP for anything :)