Yeah, I figure switching houses too often would lead to a lack of unity among the Houses, so that's not too surprising. But the shadow weapons? Even if there are alternatives like that, you never know what might happen. You might be alone without any bullets or anyone to magic another weapon up for you. Proficiency in making your own shadow weapons means you'll be that much safer. Plus, you'll be able to mold it the exact way you want it to be molded.