It's about whatever makes you happy imho. I paid around $95 for a custom wood mod and I thought that was about right. For me that was expensive, but well worth it to have something that probably no one else has. (the design is available to others but I don't know that anyone else would make the same choice of wood combinations that I did) To me that is more unique than buying a mod identical to others save for the serial number. But that's me. When I smoked I collected cigarette holders, lighters and cases, some very unique and antique, because they made smoking more fun. I think it's the same principle.
It is the same principle. I spent many years smoking and collecting pipes. I just enjoyed using and caring for various ones. I've known people who collected Zippo lighters. A Bic will light a cigarette. But some of us just enjoy collecting things. Collectors of things, regardless of what it is, form their own communities with other collectors. It's hard to understand or justify, for those outside those communities.