My DH is a Brit, and has always been in love with Disney. We first went in 1988, and stayed off property for a number of years. We rented houses but pretty soon the extended family in England started joining us as well, and it got crazy. The rented car (okay, minibus) to Kissimmee and back every day was killing us, so we started with the treehouses at WDW, before it was Saratoga, before it was even Disney Institute. We loved the extra space, the kitchen and living room facilities, and of course, the proximity.
Where it became obvious that we would be vacationing in Orlando frequently, I started looking for more economical options, and in 2002, we purchased 300 points at VWL. We loved staying at Wilderness Lodge, so it was a natural for us. Have never regretted it, and had added on since.
If you need financial proof to convince your other, there are plenty of math geeks here on the boards who can give you the ammunition. But seriously, most purchases are more emotion than logic, it's just a happy coincidence that logically it also makes sense.