I don't know if the experience is the same to pay a visit to a resort compared to staying there for a week or so. As I stated earlier, financial concerns may come into play when deciding off-site or on-site but the casual visit doesn't equal staying there.
I also look at my hotel/resort as more than just a place to sleep. I'm planning to spend 11 days in WDW in August and to stay in the parks from opening to closing every day would be crazy to me. I'd be completely burnt out by the end. I am on vacation to relax after all.
I like to go to the park that has the early EMH in the morning, stay for a while, go back to the hotel and relax for a while. My kids love those afternoon swims in the pool! Then I head back to the park with the evening EMH hour. It works out very nicely for me and I end up having a very relaxing visit. Using this type of itinerary has me spending time at the hotel/resort besides just sleeping and to have a wonderfully Disney themed resort adds to the pleasure and the magic of my trip.