Focus can do much more than DND though.
First, if you already set sleep schedule in Health, Sleep Focus will kick in automatically. You don’t even have to set it up, which is nice.
Second, I have set up Focus for when I’m watching video I don’t want anyone/anything disturbs me. So I set one up that when I use video apps like Disney+, HBO or TV+ this “Entertainment Focus” will kick in automatically. This has never been possible before.
Yes, I can turn DND on manually but it’s a drag to have to do it 4 or 5 times a day everyday.
You can even set it up that this Focus will kick in if you wear AirPods in case you always use AirPods to watch movies. To me this is one of the best feature of iOS 15.