I think there are two perspectives on this...and if you'll forgive me for disagreeing: to me, not EDCing a $500 custom light is like buying a Ferrari and letting it sit in the garage
I would assume all the custom builders make lights that are meant to be used for what they were intended. I can also feel the custom builders squirming in their seats regarding the "why" question.
For me it's not about features and price point. I just bought my first McGizmo and the reason I bought it is I want to participate in the history of the maker and the light. In general I like to buy things made by someone I "know" as opposed to a giant faceless company. I also like the idea of knowing that person cares about the product they are making and that it's an extension of their values, personality and perspective on the world. When I buy a suit I get it custom tailored (It's cheaper than buying a fancy brand) because I get what I want, I can look the guy in the eye that's making it, shake his hand for a job well done, and be on my way knowing that I just bought something from someone that's passionate about their craft.
Same reason I have a custom fly rod. Same reason I have a custom bike. Same reason I have a custom knife. Sure, they are expensive, but they will also last me a lifetime and are simply a pleasure to use. I smile every time I pull my flyrod out of the bag and see my name, hand lettered just above the grip. I only have one more point
If I have a problem with anything I've had custom made (assuming the person is still around) I can get in touch with the guy that literally made it and ask him my questions. I can't tell you how much better that makes me feel (even if I never have a problem) than the possibility of talking to a robot about what department I want to contact and what the wait time will be. That makes me mad just thinking about it. Hmm, I think I just talked myself into one of Saltyri's two tone lights.