I would agree with the hypothesis that there is less correlation between a good candidate and their ability to perform well on a white board coding problem than any number of other interviewing methods, but to say they’re worthless warrants more substantiation than cherry picked quotes…
“coding interviews are worthless”
Aaron Stockton
11

At the end of the day, interviewing is rather like statistical sampling… you pick your metrics with the understanding that no metrics will cover all possible scenarios. Whiteboards are not inherently better across the board than other methods, but to the extent that they show thought processes, I think they do have some value.