Staying at a Walt Disney World resort hotel gives you the ability to do the Disney Parks at a more relaxed pace. I don't think in the many years I have visited Disney World, I've ever spent an entire day in one park.
When noon hits, it can start getting quite hot, so this is the time we choose to leave and head back to the hotel. This is a great way to reduce stress (if you get stressed at Disney World) and help you have a more relaxing time. Spending a whole day at the park will feel like a long day, and you'll be completely exhausted at the end of it (rather than a bit exhausted). We don't want to feel that way. So we get up like spring chickens first thing in the morning, go down for breakfast at 7am and then hop on the bus to the park we want to visit that morning. After noon, we then get the bus back and come back to the hotel. We either chill out in the quiet air-conned room, go down for a dip in the pool, or go to the bar for a drink.
After an hour or two when we're refreshed, we hop back on a bus and visit a different park. When you're staying at Disney for over a week, you have the luxury of not having to tackle a whole park in one day. Just do a couple sections, go back, chill out, and then head out to do the rest or to another park.
Of course, if you're staying outside of Disney, it won't be beneficial to do this. You'll most probably need to have a full day there, which I think leads to a much more mental and physically exhausting holiday. But that's just one of the great benefits of staying at a Disney resort.