Non-owners cannot rent points, as they can be used only by
DVC members. Non-owners can rent a reservation made using the points.
A rental may not always be available when you wish to go. Since all DVC reservations are based on availability, even members can't always go whenever we want to but, with advance planning, most members are able to get exactly what they are looking for- especially if they are flexible with their dates, room type and resort. There are some looking for rentals in late November and early December who may not find any availability.
As already mentioned, renting from a member is similar to renting anything (cars, homes, hotel rooms, etc.). It allows someone an opportunity to do something without the responsibility of ownership. You can also rent DVC rooms directly from Disney.
DVC rentals for point based resevations will not get daily housekeeping and the rental policies are negotiable between the parties involved. Often financial savings can be found with a rental, sometimes there is little or no savings.
Renting is expressly allowed in the DVC documents, with the warning that no assistance will be provided by Disney and that members who wish to rent are competing with Disney in that endeavor.
Just post the resort, room type and dates you're looking for on the Rent/trade Board and see if a member can assist. You can also respond to an offer to rent by a DVC Member.
Enjoy!