What in game advantages does owning a residence provide?

[Nicodemus_Mercy]

Something else not mentioned is that you can stable and train your chocobo. I might be wrong, but I'm pretty sure it's required to go from a rank 10 chocobo to a rank 20.

The stable is not required to level to 20. It is merely a way to get xp without having your chocobo with fight you. One an hour both you and one other person can feed your stabled chocobo giving an amount of XP based on the cleanliness of the stable. What is required to get your Chocobo beyond level 10 is a Thavnairian Onion for each level after 10. If I recall correctly, quests can provide 2 of these onions. The other 8 will either need to be purchased from the Market or grown in your own flower pots. The seeds to grow Thavnairian Onions can only be acquired through crossbreeding which required access to a House's outdoor garden. So if you don't own a House or have access to a garden in someone else's house, your only option to obtain those seeds to is to buy them from the market... and in that case you might as well just buy the fully grown onion instead imo.