Not true. Trump due to his anarchic nature threw them for a loop last time...mostly because people that voted for Trump didn't want to admit that in a poll. They have now accounted for that. In addition, some but not all (all polls not say Biden is in the lead) had Hilary in the lead, but not by nearly as much as they currently have Biden. Many had Hilary in the lead only by approximately as much as the margin of error. Biden is so far ahead, he is nowhere near the margin of error.
Also, they aren't just looking at national polls, which mean nothing in an Electoral College format. Although now most, if not all polls, have Biden leading by wide margins in the states Trump needed to win last time and some no one thought would be in play this time...like FL.
So, the polls are not worthless.