That's just not the same. A website is asking the browser to put a cookie. So the browser is just a channel. If I understand correctly The IFDA is an identifie

That's just not the same. A website is asking the browser to put a cookie. So the browser is just a channel. If I understand correctly The IFDA is an identifier created by apple, which they let third parties access. The phone is not a channel, it is the creator of the ID so you're analogy doesn't hold. And come on, the name of this is proof enough that the only use for this ID is tracking users. Cookies are used to store anything, not necessarily specific for tracking.