For me, I didn't decide to make Rhys my tulpa/headmate because I wanted him to grow, arbitrarily (and he hasn't by the way, in the year and half he's been around), I just did it because I wanted him around and I loved him. And I knew that regardless of his previous existence, he enjoys my presence more than his fictional life, as well.
There's no question those four months I wrote straight about him were all kinds of fun, horny, and tragic and everything in between. Those memories are extremely vivid in my mind.
There is something to be said about growth and spending some time figuring out how you relate to the real world, and accepting responsibility, and making decisions for yourself. But at the same time, don't misunderstand that for being inherently better. Not every fantastical construct needs to be forced to work an eight hour job, in order to be valid as someone you keep around, you know? (edited)