It is just a counter for what the drive is rated for (theoretical) worst case scenario of wearing out, ignoring instant catastrophic failure - one of the review places (not sure if if was Serve the Home, or Tom's Hardware, or Anandtech or who - but it was way before Chia) did a SSD burnout test a few years back and most of the drives kept working past the zero point, some dramatically past it like more than doubled their "write limit" and I think the "winner" passed the 1000% mark.