Shooting at ISO 1600 and not 3200 is the point. Amongst others.
Thanks for the answer, instead of just attacking me for asking the question.
I'm trying to think though, even in candlelight I can shoot a 35/1.4 wide open 1/15th on 1600 film (and did so 1000s of times). At 14-15mm, you wouldn't even need IS to be on to obey the reciprocal rule.
At 3200, you'd be at 1/2 a candle.
With IS of say 2-4 stops, you'd be at 1/8th to 1/32nd of a candle.
I agree there must be somebody somewhere who would rather take a shot in 1/32nd candlelight at 1600 instead of 3200, but would you at least agree that this isn't going to be a common type of photography? If this is an actual drive for sales I'm happy to believe it. I just want to clarify that you're saying this is important enough that f/2 be offered, and indeed the reason perhaps most worth mentioning as it's the only one you mention?
What are the "amongst others?" Again happy to hear you out and learn something. To be clear I don't see the purpose of it, but I'm not saying there's no purpose. I'm just asking what the purpose is (besides the reason you've already kindly given).