I doubt that Traz pertains to this guide at all, since it's about getting an Arc to level 80. However, to address your thoughts about it, it is definitely worth having. You can make some room by deleting a couple of cultural buildings in addition to 2 of your Crossbow Ranges. You should keep the 3rd one until the Traz provides you with some, then delete it, too, and just go with 1 Rogue Hideout. This will generally allow you to fight all the way through level 3 with a decent attack boost, thus saving you the goods you mentioned. And, as you level it up, it will dramatically decrease your need (especially in HMA) for culturals/decos.