"Ghost gun" is just a pejorative term invented to make "homemade firearm" sound more spooky. You have taken propaganda hook, line, and sinker. The only difference between a "ghost gun" and a regular gun is whether it was serialized by a licensed manufacturer. While there are a few extremely niche homemade guns that could be categorized as "disposable," the vast majority are Glock- or AR-pattern firearms that use a full complement of factory parts.
It costs as much or more to finish your typical "ghost gun" than it does to build or buy a serialized firearm. They will also typically leave all the marks you'd usually expect on bullets and casings, because all the same parts touch the same way they do in a serialized firearm.
It's big and tall, not big or tall, lol. I always sum it up as "everybody is short once"