I can only speak for the UK, but it’s rarely an entitlement to have annual holidays paid, rather an option.
My currently employer will pay out if you’ve demonstrated that you’ve tried to take leave through the year and it’s been declined for whatever reason - they’ll pay the remaining balance. It’s done that way to discourage people from hoarding their days off to try and get a monster payday at the end of it, rather than work themselves into a breakdown from not having any time off work which I can see the benefit of but still not entirely sure it should be at the discretion of the employer.
That, and taking the holiday days is effectively tax free. If you take a week off on a 40hr per week contract, then you get 40hrs worth of time off. If you get it paid, then you’ll get at least 19pc of the leave pay going as tax, depending on where in the UK you are.
I’ve seen previous employers going with the flow and allowing employees to take their leave as paid if they want to, but effectively buying the leave pack at two-thirds rate for payment.
An old place I used to work for went halfway, allowing the carrying of ten days leave into the next year, but anything above that is forfeit.