I'm currently at a company with unlimited PTO, and the way it works in practice here is that people feel free to take random days off without having to count beans, on top of a pretty normal amount of scheduled vacation: I currently have six weeks of vacation on the calendar for the rest of the year (that's more than I would've liked, but I have a few important family things going on overseas). On top of that, I'm taking this Friday off for a visiting friend. This unavoidably means my career will be worse off than if I had an extra couple months of productive work this year, but I'm an adult, capable of making this decision to trade off marginal career success for marginal quality of life improvements.
It's beyond me that some people who don't want to take responsibility for their careers are so desperate to tear down policies that treat employees like adults capable of making their own decisions. It's not like unlimited PTO is being offered to those who are one paycheck away from starvation. Take a normal amount of PTO if you want, take less or more if you want, but don't pretend like this choice being offered is exploitation.