You are right, that is quite an omission on my part. Just note that the higher clock speed isn't a priority in _my_ books and brings lower battery life which _is_ a priority for me.
... but still, why upgrade the clock speed if it's a net detriment to you?
If you're making the comparison for yourself, why up the clock speed unecessarily, if you know it causes problems for you?
If you're making the comparison in general, then it's not really an excuse that you were doing it for yourself to omit the benefit of the significantly faster clock, particularly since you're drawing attention to the negatives of it (shorter battery life)?
Please don't interpret this as a serious attack or anything, I just find it a little odd.
The upgrade I chose for the MacBook Air still includes a power-efficient CPU, probably with the exact same TDP rating, just a slightly higher clock rating. This will most likely not increase the power drain, depending on what task your putting it to.