Exit polls are like a canary in a coal mine. They can show evidence of manipulations that might have happened. If an investigation finds that no such manipulation seems to have occurred, then no harm is done.
Unfortunately current US elections are unauditable because voting machines DO NOT produce any kind of verifiable voting trail. Furthermore the apparent conclusion of the US media is that past discrepancies are evidence that their exit polling is flawed rather than that the voting process is being manipulated. (They are biased to decide that way because accusing the winners of manipulating the vote - even if it is true - pushes them away from the appearance of neutrality that they try to keep.)
Furthermore you can't do exit polling on mail-in ballots. So this potential signal of flawed elections is being lost at the same time that manipulation of elections is becoming even easier.
Personally if polls are overwhelming, and elections are in line with polls, I believe the result. But I believe that there are lots of people trying to slip a thumb on the scales, so if polls are close, I am dubious about the results. I personally believe that current evidence is that the Republicans are more successful in getting their thumbs on the scales, so I'm doubly suspicious when Republicans mysteriously do better than polls indicate they should.
I want us to have elections that I trust. I do not want crappy election machines. I want verifiable paper trails. I want random spot checks. We know how to run better elections than we do. We don't because nobody wants to put the work out. I want us to put the work out.