Why is Macauley Duration a better measure of duration, especially in the context of zero coupon bonds?
Not sure what you mean. MacDur and ModDur measure different things (i.e. weighted average time to get your cash flows and a change in price for a change in YTM, respectively), or am I mistaken? And for a zero duration = maturity since you will only receive one cash flow at the end of the period.
Depends on your definition of “duration”