I don't think it is. I think if someone says they have a computer, it needs to be a computer, not a very large slide rule. The same applies to "breakthroughs" and "milestones": a non-quantum computer is never a breakthrough in quantum computers the same way a slide rule isn't in computers.

I think we're talking in circles, I just don't get how anyone can take these things seriously...

But quantum supremacy is not a general purpose quantum computer or anything close to one. At best its a proof of concept that you can do something a classical computer cannot. Certainly a neccesary condition, but miles upon miles away from a practical quantum computer.

Maybe the point is that the press/computers really ran with the "quantum supremacy" thing and severely mislead people as to what it actually means. Which i would agree with.