I'm not American so everything I read here is usually a nightmare scenario. I've seen people describe “unlimited PTO” as a good benefit. It instantly sounded sinister to me.
In my country the average vacation days per year is around 30. The thing is, employees are encouraged to take them all every year.
If you have unlimited PTO it can't actually be true. No company would look by as an employee only came to work one day a year and took the rest as PTO. So it immediately becomes a contest of how much vacation you want to take, but still keep up a good standing with the bosses.
So it's much better to have a set amount of PTO that employees actually strive to take instead of that weird vague setup, where you still have to worry whether you appear lazy.