I think that's such a great method, since it doesn't rely on state officials to make judgment calls about whether or not to count something as a COVID death in a case where it may have been a complicating factor but not necessarily a determinative one. Also, because states have had VASTLY different rates of testing, states with higher testing rates were more likely to declare a given death a COVID death, which further skews data from one state to another (and from one time to another..... like a COVID death was less likely to be recognized in early 2020, before we had widespread testing, than today).
With excess death data, none of that matters. It's just a question of counting bodies, regardless of cause of death, and then comparing the rate to the background rate.