Just because something isn't perfect doesn't mean it has no value. Polls communicate experts best guess at how the vote is going to turn out based on the data they have collected. It's likely to be a lot more accurate than a non-experts guess, or even the guess of an expert without any data. It's also not even possible to share the raw data because of privacy concerns.
The forecasts you see on sites like 538 and the economist are even better, because it doesn't just communicate experts best guess (democrats win by +7), but experts best guess at how accurate that guess is too (something like democrats win by +7 +- 6, except in a lot more detail and nuance).
On HN the catchphrase for this is basically "don't let perfect be the enemy of good".
The forecasts you see on sites like 538 and the economist are even better, because it doesn't just communicate experts best guess (democrats win by +7), but experts best guess at how accurate that guess is too (something like democrats win by +7 +- 6, except in a lot more detail and nuance).
On HN the catchphrase for this is basically "don't let perfect be the enemy of good".
Note: I made up the numbers in this post.