Some people work night shifts

And the people that do work night shifts, have their shifts either shortened or extended by an hour as well (at least in Germany, from what I’m aware)

Before companies went global 24/7, this was really a rare problem.

These days, you could have a global company where some emergency occurs and you have to call a meeting at sometime on Saturday wrt your location timezone, but one of the other locations is several hours ahead of your timezone such that the meeting occurs during/around the transition period for their location's timezone.

So, not common at all. But it may happen. That's why they choose the transition times to occur when most of the LOCAL population DOES NOT schedule meetings.

I don't think there were any Saturday/Sunday virtual meetings when this timezone stuff was created... Simpler times...