The surprise was the delivery vehicle/method it was launched into orbit and then deorbited to hit a target.
Basically what China just showed is that they are capable of parking these in orbit which would both greatly increase their effective range as well as reduce the signature making them far harder to detect and intercept.
It’s basically another Sputnik moment for the US. When the USSR launched Sputnik the US was scared that they’ll launch a bunch of nukes that they would be able to bring down on the US at a moments notice.
Keep in mind that back then ICBMs weren’t really a thing yet not to mention a full nuclear triad and that the US had to mainly rely on its bombers to deliver nuclear weapons and its defense primarily focused on shooting incoming soviet bombers.
If China parks a bunch of these in space it would mean that any US naval task force or ground force anywhere in the world is now at risk.
That’s quite a tectonic shift in the balance of power, and if anything these articles probably downplaying the actual impact something like this can have.