Standard working hours are set in contract terms, or should be.
This is an extra limit of a maximum ten hours overtime for most people, losing one of two rest days, on top of regular hours.
Pulling back from a sixty or seventy hour working week (which I was often expected to work on a regular basis by my local government employer), to a legally enforced maximum 48 hour week meant my employer had to employ more staff, or close the establishment.
They employed more staff, because they could no longer exploit the staff they already had, because of the working time directive.
It really was that simple, and the legislation works, healthier staff with a work life balance.
Many employers exploit their staff through overwork.
If the employer has sufficient staff overall, and does not routinely exploit staff regarding working hours, it should not be an issue.