As you might or might not be aware, there are different time zones around the world. And while 1:30 PM PT might be a good time for making hotfix in USA, it is definitely not a good time to put EU servers down. Really, think about it...
They do not have to shut them all down at once, but it's more expensive to individually shut them down .
Precisely. And from a business perspective, the more efficient, cost-effective practice has been chosen. Some might not like it, but I understand the scheduling and can tolerate the downtime. Especially since it gives me an excuse to take a break, and catch up on other things in the meantime.