Isn't it all about the odds? Spinbot will accept up to 10SBD/STEEM per day and will credit you with it, increasing your probability of winning its affection (upvote). But 2 days per week it will upvote completely randomly adding a socially progressive element (robinhood like even..). Investment made in the bot will cover expenses (for delegation, hosting etc...) and be reinvested into making it even stronger. There is an inflationary element but what if you had a 1/1000 shot of winning 100$ twice per week and it only cost you 1 steem to get in the game? Do you feel lucky?