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Indeed I also never participated for the same reason.
But when this concept came to my mind I had to :)
And as said: the investment goes into steem with a minimal chance to win a higher amount. That's why I see it as a win-win situation.
An investment that at the end doesn't cost anything but brings profit for several people - directly or indirectly.

This seems the best way to do it indeed. Especially when it leads to a nice contest ;)