If Whatsapp media messages are e2e encrypted, what is the point of storing popular messages on the server?

There is something I don’t understand about whatsapp’s privacy policy.

Your Messages. We do not retain your messages in the ordinary course of providing our Services to you. Once your messages (including your chats, photos, videos, voice … Continue reading If Whatsapp media messages are e2e encrypted, what is the point of storing popular messages on the server?