I see @steemsports as a sort of "cloud mining" service, in that it's so easy for others to "mine" (obtain by a means other than posting/curating in this instance) STEEM.

The "rake" could be considered each users payment to the cloud mining service, and this STEEM based business appears to be very popular. Probably because this "mining" service also adds an element of fun to it and allows the "miners" to increase their odds of "mining" some STEEM by doing a little "work" (aka research or "tweaking of the settings" lulz).

BTW, isn't mining based on "luck"? (that's for @noisy). ;)