Family Sharing, introduced with the release of iTunes 220.127.116.11 on October 16, 2014, allows the sharing of purchases from iTunes, iBooks, App Store and Apple Music Subscription with up to six people in your family – without sharing accounts or passwords (official description
The obvious, official, supported, and intended use of Family sharing is to share iTunes purchases among family members; however, there is an unofficial, undocumented use for Family Sharing as well - Family Sharing Clubs
Ideally, a Family Sharing Club would allow you to 'pool' purchases with a group of like minded collectors, the purpose being to give each member access to a much larger 'pool' of available content; whether that is apps, movies or TV shows. I've been the organizer and member of such a club since Family Sharing became available in 2014, which allows me access to almost 2400 movie and TV shows, substantially more than I would be able to afford on my own.
As the organizer of a club has to have a payment method on file, there is a certain amount of trust that individual members will maintain an iTunes balance to cover any personal purchases and will be liable for any charges to the organizers card. The easiest solution is for the organizer to keep a pre-paid card on file with iTunes with a very low balance (ideally less than $5) to minimize the risk. And as an organizer, there have been isolated incidents over the past two years where a member has had insufficient funds to cover a purchase, but each member has made good on any overages.
For me the benefits of being in a Family Sharing Club far outweigh the small inconveniences as it is rare that I don't have access to the latest releases without having to resort to renting
There is an exhaustive write-up of the Family Sharing Club concept by Yumbo of Blu-ray.com here