It's not like the PC version was ready. It has issues that can not be fixed in another 6 months of development. But as bad as the PC version is, it's at least somewhat playable in contrast to the console version.
I've watched a few streams; while there are bugs, they are more of the variety found at Skyrim's or Witcher 3's launch. Annoying, frustrating maybe, but not to the point of making the game unplayable as it stands on PS4. The severe performance issues appear to be solved by just flipping a setting or two.
I believe tsss is referring to things such as terrible AI on PC, and other complaints about the game such as a lack of interactability with the world outside of quests. Not bugs necessarily (although the AI certainly is in a grey area) but issues with the game, certainly. Whether they'll be fixed remains to be seen
It could be like a Bethesda game where there’s more bugs than actual game content, it’s never fixed, but nobody actually cares because everyone plays with a hundred mods.
Witcher 3 was very buggy on launch, the bugs were fixed over time and it runs flawlessly nowadays.
Skyrim still has plenty of content-related bugs (i.e. not graphical or performance related); Bethesda never fixed them but oddly enough, modders did and you can download a bugfix mod from Nexus or Steam.