While I will never claim to really understand collecting, it's been my observation that for many collectors the process of acquisition is at least as much of the appeal as the possession itself with each item having a story about how it came to be theirs.
Otherwise there can be the sense of completion - filling out a lineup of all the colors, options, models of interest. I'm mildly guilty of this having obtained a set of OG Emisar lights - D1, D1S, D4, D4S - but they're either regular users or merely inactive once I determined they didn't really suit my needs (i.e. the throwers). They might sit within a cabinet moderately dedicated to flashlights but they've all been scuffed, scratched, dropped, etc.
Some seem to see it as an investment of sorts. Based on some of the BST activity I've seen here and elsewhere there are some high-end / custom models out there that have good odds of appreciating over time - perhaps at a rate better than inflation. However if making money is the goal one is probably better off making actual financial investments.
