Excellent info, I have a nice sea anchor with some chain to keep it down. My transom is tall but the scuppers are dink’s.As already mentioned, if your boat drifts with the transom to the wind then you need a sea anchor of some sort to be able to change the orientation of your drift when needed. This is especially true with notched transoms in rough conditions, as these boaters discovered.
Personally, I favor a notched transom in bad conditions because I can dump a lot of water over that notch very quickly. I operated lifeguard surf rescue boats here in San Diego and Australia, and they all had notched transoms for that very reason. Those little deck scupper holes don't cut it when you have a large volume of water on the deck that needs to go out.
I think many boaters don't even know the purpose of a notched transom or how to take advantage of one in these kinds of emergencies. They don't act quickly enough and then the boat is swamped, or critical equipment has been placed where it is easily compromised, thereby eliminating any chance of self rescue.
The only downside to a notched transom is that you need to be mindful about exposing your ass end to bad weather. My boat will do that if left on its own. That's where the sea anchor comes into play. I keep one on my boat at all times in case my engine fails and the weather gets nasty. It keeps my bow into the weather 100%. I also have it available to slow my drift for bottom fishing, or for those times when I want to keep fishing despite some bad weather.