Some of us have plain old Phantom 3s because we can't justify the cost of the "fancier" ones. And we have a great time with them. For most people it is an expensive toy.
You are correct. There was a time when a deep discharge was necessary due to the fact early rechargeable batteries had a memory affect that necessitated a deep discharge occasionally to allow the battery to accept a charge to its full potential. The LilON cells should not have that requirement...