Server limitations are for when people ask for things that the system the devs have in place transfers with your character every time you change instances/go into a dungeon. This isn't so much a "server limitation" but a write throughput limitation. The devs are simply using language that most people understand. I'm sure most of the playerbase would have their eyes gloss over if they started talking about iops, network transfer limitations, SAS transfer speed limitations, disk write limitation, etc. (this can also tie in to player network limitations, a la people dcing en mass at fates due to their own set-ups not being able to handle the sheer amount of data being transfered, I've never dc'd in those circumstances.)

Also, ps4 is stronger than a lot of players crappy college laptops they use to play the game at 15fps