I don't see housing as a top priority issue. If anything, I don't think housing has been given enough priority because they are working on so much other content instead. The evidence is in how many times the housing related patches and fixes have fallen short of people's expectations.

If you're asking why the dev team bothers with housing at all, I think it's the sense of permanence. Players like to have something in the game that is uniquely theirs. With equipment that's barely possible, outside of glamours that anyone can mimic if they have the gear or the time to get it (except certain unique / rare rewards).