The `daylight saving` purpose is intriguing. I'm very curious why people long time ago, decided to change clocks, instead of work/school start and finish times. Like we start in April at 8:00 am, and in November, at 9:00.
That could cost less today because we use much less paper, but updating web sites and databases is still a large amount of work. It's far easier to communicate to all the country when to move the clock and keep everything else the same.