It is a financial decision, but not an investment per se.
Basically, DH & I were going to WDW 2x/year, for a total of 12-20 days, staying in at least a moderate hotel.
We bought DVC because we like the ability to "spread out" a bit in our unit...even the studios are bigger than a regular hotel room, and have the little kitchenette. If you go to a 1 or 2BR unit, it's like a condo. Once we paid off the original loan, it began to make greater financial sense.
1. You don't have to come up with a fairly large "chunk" of money for your accomodations each trip. In our case, our dues are debited right out of our checking account each month. For some reason, that is less "painful".
2. You end up getting a superior accomodation, IMHO.
3. You do have the ability to cook in your room. We do breakfast and snacks, but there are many folks who also throw together simple dinners a few times while they are there, at a significant savings.
4. If you are in a 1 or 2BR unit, you have a washer/dryer, which makes packing easier.
For us, DVC has been worth every penny we have paid for it. We have enjoyed it with family and friends, and have many wondereful memories. It is willable as well.
It is a purchase we have never, not even for one moment, regretted.
Truthfully, I would give up a lot of other things in my life before I'd give up my DVC!