Last week tonight did a good section on prediction markets this year. Tldr yes they are gambling sites, but the name is rooted in reality. Basically, farmers could pre-sell their expected crop yields, aka "futures". The futures holder could then sell that pink slip to someone else, aka a "futures market" or "prediction market". Societal leaches saw Draft Kings making shit tons of money and figured they could make shit tons of money by opening it to all aspects of life and argue in court it's no different than the future markets of crop sales.