Ok, here's the scenario. You're the thrower in the middle of the field. Your stall count is on 5.
The marker is forcing straight up on you, knees bent, his long arms spread out wide. A cutter is running straight at you from 20 metres upfield. He is very open.
A wide release backhand would be really tough because of another cutter clearing out nearby on that side with his defender, and your marker's large wingspan.
A wide release forehand would be tough as well, because your dump's defender is near that side. And you have the big arms of your marker to deal with.
Do you have a high release throw that can hit this cutter?
If your answer is "no", then you likely have to turn, engage your dump, and your team will reset the offence.
If your answer is "yes, I have a throw for this" then you can gain yards, and can attack (because throwing is a great starting place for a cut, whether it's cutting upfield 8 metres for a dishy pass back, or a long cut deep or flaring wide to draw your defender out of there).
The throw only needs to travel 10 metres. A little float to it will make it easier to catch. It is only a "twitch" throw (requires no significant wind-up, or repositioning of your torso by lunging etc).
Twitch throws give the marker no time to react if you have the disc in a position ready to release, and they don't have their hand in the way. Twitch backhands seem like a big new trend for North American elite open ultimate.
I have thought about this scenario a bit, and seeing how often a "no" slows down the offence can be painful to watch. I have thrown more and more scoobers in the last 12 months in this scenario, which is a throw from either forehand stance, backhand stance or while pivoting across.
And I am working on getting more and more high backhands and high forehands out (for the backhand and forehand stances respectively). One way to get there - lots of three man drill (aka thrower-marker drill), making sure you are in ready stance and with the stall count coming in on 9.