It's a shame that you're being downvoted, because you are correct.

> But Brantner said research indicates that employees with unlimited vacation tend to take less vacation each year than workers who have caps on their vacation days. This, she said, is partly because many companies have policies requiring those with limited vacation days to use those days or lose them at the end of a calendar year, which encourages those workers to take off all the time they're allowed.

> The 2017 HR Mythbusters report by Namely, which offers HR software and services to midsize companies, found that employees who were offered unlimited vacation took, on average, 13 days off a year, while workers with capped vacation days took, on average, 15 days off.

https://www.shrm.org/resourcesandtools/hr-topics/employee-re...

> A rundown of research compiled by Sage Business Researcher showed that companies offering unlimited vacation found that in many cases it actually encouraged employees to take less time off. Other research shows that it may even create competition to take fewer days off.

https://www.inc.com/john-boitnott/unlimited-vacation-sounds-...

"Unlimited vacation" is not actually unlimited. Hear it from Joshua Reeves, CEO of ZenPayroll, which offers this benefit to their employees:

> Even if your time off is technically “unlimited,” your manager obviously doesn’t expect you’ll take off 75% of the time. Actually, he or she probably has at least a general range of number of days or weeks in mind that is acceptable for an employee to take off—even if that range hasn't been openly communicated. Similarly, your company may expect you to take a minimum number of vacation days. At the company HubSpot, for example, employees are expected to take at least two weeks off each year under its “two weeks to infinity” policy.

> To get a sense of the norms, ask your boss (or other colleagues) how many days or weeks other employees typically take off. If the theme seems to be “2-3 weeks, plus a day here and there,” stick to that. If you have any doubt about whether you’re using the vacation policy appropriately, pay attention to how your manager and those around you use it. (Of course, be careful: Some workplaces do have different rules and expectations for managers and their reports.)

https://www.themuse.com/advice/unlimited-vacation-policy-wha...

So if the company has an idea how much vacation you should or should not take, why call it "unlimited"? Because it's great marketing (for those who don't think about the above factors anyway), and because vacation that is not accrued does not need to be paid out. Back to that SHRM article:

> Some organizations, Brantner said, began offering this benefit as a way to get around having to pay workers for unused vacation days when they left a company.

> "I'm absolutely sure that it originated in some camps as a way to get a vast amount of vacation time off the books. It was something preferred by accountants and others looking at the bottom line. At the same time, there are companies that adopted it with good intentions and that believe in the value of taking vacations."

> In November 2017, the Financial Times reported that "a big firm that ditches fixed paid leave for open vacations can wipe millions of dollars' worth of unused leave liabilities from its books that would otherwise be paid to departing employees. At the same time, it can safely offer bottomless holidays knowing most employees will never take them, especially in the U.S., the only major advanced economy in the world that does not guarantee workers paid vacation time."