I agree. I've now worked for two companies with unlimited vacation policies, and there have been some stark differences. At my previous job, where there was previously an accrued vacation system that switched to an unlimited policy, no one felt good about taking vacation days. At my current employer, everyone from the founders on down advertise and celebrate their vacation. Same policy, different context.
From an hours-worked-metrics standpoint, the policy is a success at my previous employer and a failure at my current job.
From an employee-health and burnout-rate standpoint, the policy is a failure at my previous employer and a massive success here.
I can't advocate either policy over the other without that context, but I'm skeptical of the value of introducing unlimited vacation as a benefit over an existing accrued vacation policy that employees are generally happy with.