My big 4 consulting firm did not pay me a dime of saved leaves when they laid me off -because unlimited PTO

Another company which had set 22 days a year paid me the balance of pending 6 leaves when they laid me off .

In both cases there were department wide layoffs but the one with set PTO at least paid me for that.

"Unlimited payed time off sounds great - can I just get it in writing that it is OK for me to take 6 weeks off over the summer every year?"

I have unlimited PTO and take 6-8 weeks a year. There are employers where it’s not smoke and mirrors.

I think you answered your own question: it's a scam to enable the company to save money and reduce actual vacation days.