It was kind of a trick question, it implies that "all else is equal" but the crow/no crow.....and I don't think crow works that way.
I think they are basically behaving as spoilers. That provide a steeper decent angle (without excessive speed buildup) by reducing the lift to drag ratio. With a steeper decent, any error lining up with the touchdown point will not result in a long error down the runway (like you would have with a flat approach).
I am not sure how they improve stability, I am sure they do I just dont understand it. They amount of crow would be close to the amount the TE would move if you twisted a couple of degrees washout into the wing tip, so maybe >1/8 inch? Most crow is going way way more than that.
As to the original question, I think the crow actually increases airspeed (all else being equal) because you have less lift available therefore need more airspeed to have the same lift force. But in a steeper decent, your groundspeed may actually be less. Who knows