With these i guess the difference is the scope, in traditional bet you only can bet is the actual game itself just the winners of the matches but recently people want to seek more which is with the polymarket that offer additional criteria of bets which people wants like as first winners on map 1, match end and etc. So its has more options to the people to put their money and chance to win, still both entertainment but of course depends on preference.
Rather than preference, I would see it is about opportunity seen by bettor for them to capitalize their knowledge on other topics which do not have anything to do with sports.
Just before a gambler is specially good at predicting football matches, it does not it mean they cannot also have the capaticity to predict geopolitical happenings.
Also, there are people who do not know anything about sports but still can pretty much into the world of fashion, so they can use these platforms to bet on beauty contests.
In the end, it is about money and way to get them thanks to our knowledge and experiences on sports and other topics which are completely unrelated.