I'm pretty sure the real purpose of a PIP, everywhere they are used, is to build up sufficient documentation to fire someone.Of course it is. As I was telling coworkers this morning, any time I've had a direct on a PIP it's to do the hoop-jumping paperwork to satisfy HR. I've already decided I don't want that person on my team. And to be fair, that's because I've already tried "performance improvement" (regular 1:1s, goal setting, the like), and concluded that more of it isn't going to turn a bad fit into a good one.
So, yeah, if you find yourself on a PIP best start polishing that resume, because you're not long for that company no matter what HR tells you.