One of the best ways for player interaction is made through houses and different sorts of events that take place there. Most interactions between players is done by the use of emotes and chat which can ruin immersion for some players that enjoy talking over texting but the implementation of said feature cannot be added in all of Eorzea since the high amounts of players that are located in most cities will make interacting with this feature impossible. That's why the implementation in houses where people have more control over the people that join them and the amount of people there would be significantly less than most cities the game has to offer making it a reasonable way of interaction. The feature can even have some settings for home owners (They can decide if their house will have Proximity Chat or not for whatever their reason may be) and players alike to be disabled if they don't want to use it.