I ride an EUC that has a top speed of around 30mph, it's a couple years old (a Tesla V2) and the current crop (prior to the model in the article) are all capable of 45mph or so. I feel safe on mine and ride in urban traffic, and everyone I know that rides is very safety conscious. To see some examples and see what's up with Electric Unicycles on YouTube check out Chooch Tech, Wrong Way Zen Lee, etc.
https://youtube.com/c/choochtech