Of course the sequence of events matters!

If you log in to a Dice site, make a deposit of BTC and roll, you have no idea whether the wins/losses of the people before you will mean you will find yourself fortunate enough to be joining in at the best time in the algorithm or the worst. Your wins and losses are not knowingly dictated by the players before you, although they are a factor, the players before you have no way of knowing how their playing will affect your playing.

If you join a Ponzi and send money in, you then have to seek out other people and convince them to send money in so that you don't end up being the user who doesn't get paid. The purpose of joining the scheme is to *not* be the mug who doesn't profit, so you have to post encouraging words in their threads to rustle up some other people who, through your post, will be encouraged enough to send in their money, resulting in some of their money being shared with you.

Your profit comes, not from a provably-fair algorithm unaffected by other players but, instead, a mathematically unsustainable process of finding other people to take the fall for you.