Hi, please know if it’s link only answer it may get flagged easilly. Please share a picture in worst case of what the answer look like.

Thanks for everythings, I have no words, but my english is not the best too, but most of all I'am wishing you a speedy full recovery. Take care man

Hi, I didnt close it, but it seem opinion based to me, but your edit add some context. For the usage itself I don’t know, but I would guess it’s because the cdn is often a thirdpart and you would not want to deleguate your own dns zone to a thirdpart as often the cdn is independant of the main site. As such we might never know the why for facebook or other brand the why they choosed that way. (the why it can be tagged opinion based for me)