Why do Vanity items / Player housing / Pets exist?

[Jess_Spark]

A Sandbox game, by design, is a game where the player is free to explore the world, create their own content, and impact the world around them. There is little to no set goals other than what the player makes for themselves. The content they create can be shared with the other players of the game and the impact they make on the world is felt and shared by all. The content creation, and ability to share it, are pretty much the defining feature of a Sandbox MMO.

There has only been a handful of truly Sandbox games. Ultima Online, Star Wars Galaxies (pre NGE era), The Repopulation, and to an extent EVE are most common examples.

Correct. That is what this game does and will do even more in the future. That's what makes this game awesome. I will play this game for years because it is Sandbox.

[Renik]

Correct. That is what this game does and will do even more in the future. That's what makes this game awesome. I will play this game for years because it is Sandbox.

It's not a sandbox, just having most content as instanced disqualifies ARR as sandbox, this game has a long way before it can be called a "sandpark", so it's really far from being a sandbox, housing is a minor detail.