For this particular contest, you have to sign up or confirm to the campaign manager that you are participating by sending your username, so there is no traditional leader's board. Yes I agree that you will need to be a high roller to stand a higher advantage but in the multiplier contests, even someone with small bankroll can get luck and hit over x1000.
With multiplier contest, it is more comfort to join and you can win the contest without need of having big capital for gambling and participating in those contests. It is really different than in wagering contests that require participants to have somewhat enough big fund for bet and accumulate enough big wagering value to win these contests.
BetHog chose a right contest type to run for community and also attract enough participants. Their multiplier contest can help them expanding their brand to more people by words of mouth.