This system serves for us to get used to how the way rested XP will be handled in the future in 2.0, as to let us 'grow the habit' of using it so it's not a huge shock. Player housing itself is not so much the issue, the issue itself is getting used to future systems.
That being said, perhaps this inn system isn't that useful, however, nothing stops SE from including OTHER things in said INN rooms, which they probably plan on. Also, they most likely did not need to divert any work frm anywhere to include this system. Probably the crew tasked with the player housing system went "Oh, look, this part of the system can be included in 1.XX. It should be ready by the time patch 1.21 rolls by, so we can add it in!"