You don't "NEED" to do any of this. If you do it it because you choose to. If you CHOOSE to be a mythic raider you're making a choice to be a mythic raider and all that comes with it. If you choose to be casual then you do all that comes with that choice. Blizzard to not force anyone to do anything. Its all choice. So in theory you don't "need" to do anything unless you choose a certain path