If you are trying to hit chains and stay within 30' that means your target is somewhere below 30', not 60'. The 60' target is what you end up with trying to stop on the ground at the base. Trying to hit chains means your closest land on a miss is AT LEAST 10' behind the basket. So really you are trying to hit a 20' target while also trying to hit the chains. Not a high percentage shot.
And let's say you actually manage to always stay C1X when you run chains. Make percentage for C1X is around 80%. Do you think that you make 20% of your field ace runs? I am betting not. If you make anything less than 20% of your field ace throws it is an objectively terrible choice to actually throw for a field ace. And let's be honest, the make % for field aces is somewhere in the 1% range.
Math. Try it.