Always be able to use heroes at CW

Hi folks,

Why is it that in Clan Wars you can not use your heroes in an offensive way, when they are being upgraded? For example, I have my King at lvl 14 right now and it is being upgraded. In defence he still works at lvl 14, but in offence I am not able to use it. Al other troops that are being upgraded can still be used during any attack, off course being at their lvl that is already completed. Why not the same for our heroes?
I see many people don't participate in wars, or only use their heroe who's is not being upgraded. If this where to chance you would see more wars with clans using their full power, because both clans ca use their best troops.

Does anybody have an answer to this?

Cheers Noustah (my clan being Dutch Error)