Newsweek has always been a questionable source since its purchase by the notorious IBT. https://en.wikipedia.org/wiki/Wikipedia:Reliable_sources/Perennial_sources#Newsweek_(2013-present)

Not to mention that a quality poll would just be among qualified likely voters in the election in question, where as polymarket is just gambling addicts anywhere on the planet.

But at the same time Polymarket seems a bit like a self fulfilling prophecy - because Polymarket says something, it by itself increases the odds of that event happening; and in the cases where it isn't this way, look for the large amount of bets 2 hours before the event in questing, a.k.a the "GOP spike".

On the other hand, it's well designed to surface inside information. Exactly the thing that lots of people complain about, but it's a good thing if you'd like to use the prediction market to make predictions like this.