When I read the question (one on MSE) I myself though of a similar answer as you have provided though you have presented a bit more nuances than I could have touched.
For PSE, "every signed scalar (quantity or state) is technically a one-dimensional vector." This is the root cause of my confusion I think.
Also, another difference that I think lies between us 2 is that from that WIRED article, I agree with the 1st definition of speed while you seem to be in agreement with the 2nd.
Scalar and vector are 2 different things and I don't think they overlap anywhere as you have mentioned though given my limited knowledge on the field I should put it as: I don't think they should overlap.
But I'll readily give that a benefit of doubt as recently I discovered that even the definition of Natural numbers isn't the same among all the members of the mathematics fraternity as some include zero (0) in it! despite the existence of whole numbers!!! (Baffled at the fraternity's attempt to not to be not confused!!!)
