Re: I'd guess along the lines
They had problems with their system that this drill uncovered - some of them sound like problems they might have predicted but still it's better to know about them than not.
Agreed. While this isn't the right way to run a drill, it did reveal problems, and according to the reports I've seen there were no related deaths or injuries (which there well could have been, in a panic). As a screw-up, it definitely falls short of classics in the field, such as the Great Disappointment.
Given a choice between recent embarrassing US government escapades, I'd take the Hawaii Missile Scare over Trump's State of the Union blathering. (Though to be fair the SotU speech is rarely substantive or interesting, regardless of who's in the Oval.)