I do it to enjoy the differences in resorts, sort of like having two different vacations in one. As I am single or traveling with another adult, it is really easy for us to pack up (generally in 20 minutes or less), call bell services and have our luggage moved for us. We head off to a park, then catch the bus back to the next resort and wait a few minutes in line to check into the next room then go exploring the new resort. I guess I am used to doing this as most of my trips have been split trips especially when I hit my 20's and took more interest in the resorts (prior to this I was just another person staying in a room jumping in the pool and hitting the parks all day long). In 2003, I stayed 8 days at PORS (and I also stayed at two other resorts briefly during the same time) and loved it but thought after the first 5 days (being that I had used the pool, slide, hot tub, quiet pool, laundry,rented a bicycle to tour the resort, boated to DTD at least twice not to mention caught Bob's show a couple of times and ate in the sit down restaurant a couple of times) that I could've checked into another resort and explored it too.
I also am money conscious and feel that if I am paying more to stay at any resort, then I will get my monies worth out of the resort. For instance, if I stay at AS then I will hit the parks heavy on those days then if I check into a Deluxe (WL) then I will spend more time at the hotel enjoying what I've paid for and less time in the parks (maybe even one whole down day enjoying the pool). I know people love to stay at the same place but I find I am happiest having a little bit of everything.