I have to agree, I don't see where this article answered the '3d' question for me.
This article states: "Sony wants to focus on delivering 3D audio through headphones first. But, according to Mark Cerny, PS5 lead architect, the console will also be capable of delivering 3D audio through your regular set-up – whether it be television speakers, soundbars
or surround sound systems
." I'm no expert here, but I thought headphones are a stereo sound delivery system to the ears.
Then later, "Sony says the effect is so powerful that you'll be able to hear where individual rain drops are landing in a game's environment. " .. well, in headphones, stereo sound gives you a good indication of where a sound came from in terms of left and right, but it can't distinguish from 'behind' or 'in front'. That's not 3d, that's 1d.
If there were positional sensors on the headphones that indicated the tilt of your head, then the software could adjust the audio according to your head position, including up to 3d in a kind of "mario kart on SNES was 2.5d" sense, giving you a more immersive experience, but I don't see these sensors or that experience mentioned in this article in the same breath. Maybe I missed something, there are details on HRTF and some very vague statements about the Pulse 3D headset, but nothing substantial.