Yeah okay, I thought they voted premium users threads "extra" and not posts - not that the other alternative is accepted in my book either. I just mean leo does seem to at least have curators behind the votes where as many of the others seem to just be running through hive.vote/ bots that determine receivers delegation to them or token holdings.
As you say, it's as if splinterlands would just auto vote whoever holds the most SPS or delegates to them instead of the content/general value user may be providing to hive/splinterlands.
Having a premium account provides higher probability that your account will receive an upvote.