It's the perception.
Maybe better quality parts as well.....better attention to detail.
Whether it's true or not, my mind "defaults" to thinking that a module made by Bruce's outfit will be of better quality than one that's mass produced. Made by hand means someone is looking at every single one of them.
Interestingly, I have offered to help local builder/acquaintance Joe Driskill on several occasions. I have asked him for a job in the past helping build guitars because he was always SO far behind. I think his wait list is like 3 years - just crazy. He has always turned me away, wanting to do it all himself.
People pay out the wazoo for his guitars that he machines and hand builds himself.
I'm sure they'd be worth much less if they were "Made by Driskill...with help from Marvcus."