Questions

Points that can be used to buy purely cosmetic items
A resource pack with custom visuals/audio
The ability to create public "warps", or points where any other players can teleport to with a single command.
The ability to not be automatically kicked for being idle on the server.
The ability to set your status as "afk"
The ability to use commands to see what direction your facing or your location in chat.
The ability to format chat messages and signs with colors.
The ability to clear your inventory with a command.
The ability to launch a firework with a command.
The ability to have any mob follow you around like a pet. The mob would not take damage and would not be able to damage other players.
The ability to ride the above mentioned pet.
The ability to name the above mentioned pet.
The ability to wear the above mentioned pet as a hat.
The ability to use a command to see which players are within a certain radius in chat.
The ability to wear any item/block on your head like a hat.
The ability to see the recipe of any item with a command.
The ability to disguise your character as any mob in non-pvp servers.

In a server where you start with your own floating island, would different island designs, with the same resources, be considered cosmetic?
In a creative server that allows players to have "plots" to build on, would extra plots be considered cosmetic?
In the same creative server, would the location of the plot be considered cosmetic?
If I modify armor so it has no benefit over having no armor, is armor then considered purely cosmetic?