There are people who could maybe take 50% of their entitlement whilst only being into the year by 20% or thereabouts, if holidays are available from April and a 2 week holiday is taken in June, as an example. It wouldn't work for everyone, even though they haven't 'earned' it by that point, if they remain employed for the remainder of the year then all of the holiday hours will be accrued eventually.

Personally, I worked for 1 or 2 employers that operated a policy like this, incidentally they were the most frugal employers I've worked for. I think it's a sign that the company is either in financial difficulty and trying to control outgoings, or they've just become frugal for other reasons, such as greed, or lack of trust, in that people have rinsed them of holiday hours and left with a deficit and not repaid it.

That said, if it works for you then make the most of it by all means, but personally I've spent 15 years with two employers who would allow the whole years allowance to be taken within a matter of weeks.