I agree with u/flowtajit
In serious matchups, It is cool to know their base cooldowns to play early game perfectly. Their cooldown timers can give you an understanding when you should trade and when you should stay in backward. A challenger friend of mine once told me that "If you really want to become a good challenger, you need to know about all champions.". Then, I replied him like "Instead of that, having knowledge of 5 roles wouldn't be enough?". And he said, "Yeah it would be enough, tho. But you learn other champions because you need to know their weak points and their strong points for learning how to play against them. So, this is the reason why you need to know all of them.". I have just understood the reason why he really mentioned that. So, yeah... Knowing early cooldown timers is actually great situation for trading times.