It is a winner take all market. All money placed in the market goes to the winner.

So if I want Donald Trump dead and am willing to pay a million dollars, I start the market and put a million dollars in for tomorrow. Eventually he dies and someone collects. Almost certainly not me, and not necessarily an assassin.

But any would-be assassin who wants can place a bet and now has a million dollars riding on whether they succeed.

This is not novel, the idea has been around for a quarter century. See https://en.wikipedia.org/wiki/Assassination_market for more.