The great thing about collecting is everyone has their own particular reasons. I can imagine most film collectors display their favorite films with exclusive packaging in prominent locations.
In my case I love digibooks or any film with an insert essay as it's nice to access information and or...
Regarding slips, lenticulars, digibooks and unique packaging (but not oversized junk boxes). It's similar to why people collect books. Books are very seldom read more than a couple times, so for most, a quick glance at the book presentation is a strong way to reconnect with the memories that...