Does it matter?

Does it matter if its not technically a 1 shot, 2 shot, 3 shot on any particular champion if they instagib kill another champion in the same time frame as a champion who is doing a 1 shot, 2 shot, 3 shot. If there were significant cooldown times and the champion couldnt immediately run with no way to fight back for most champions then maybe it would matter that some one with long cooldowns blew their spells. most champions dont have any siginificant cooldown windows to exploit after level 8 or with any cdr except most fighter tank and support champions.

Largely refering to champions who benift from attack speed without having to build defenses and those who have spells under 3 seconds cooldown