The short of it is that the shell FC goes against SE's intent, and it's also making a bad situation worse. Additionally, shell FCs are a known vehicle for unsanctioned housing RMT - and unsanctioned RMT is generally bad for the health and stability of an MMO and invite some of the bot and inflation problems like what was observed in Classic WoW recently. Unsanctioned RMT also invites in a ton of GM related issues with account theft and other shenanigans.
With resources as scarce as they are and as many new players as we have seen (region breakdown on total characters rolled is NA 2,378,009; JP 1,395,530; EU 1,112,159 - Yoshi-P also cited this in
https://na.finalfantasyxiv.com/lodes...0acb6c23ccd07f ), so while it may not exist now (as many of the WoW refugee sprouts are able to purchase houses yet), this is going to be a problem in the future as many are likely to stick around for a long time. Lookig at the restrictions at
https://na.finalfantasyxiv.com/lodes.../housing_land/ , SE seems to indicate that each service account should have a single personal house, specifically:
The problem here, however, is that the FC system is so loose that it's trivial to bypass that even with the restriction in place. The real impact of all of this is around 10,042 to 27,768 properties can be considered shell FCs (depending on the criteria for a shell FC - data from
https://www.xivhousing.com/ ), which means that it's displacing that many home owners from joining the system and also denying properties to the legitimate FC owners. That's between 7-22% of all the FC properties worldwide being shell FC properties.
The other issue here, if that number does not have a high degree of certainty that it is only comprised of shell FCs, it's going to do a lot of collateral damage if SE were to, say, demolish all the homes identified as shell FCs.