Besides what Sal said:
You would not have a home resort advantage at any WDW resort, meaning you would only be allowed to book at the 7-month window. This means you would never be able to get some of the more popular villas/dates that always book completely by home resort owners. The best example of this would be a standard view studio at BWV for New Year's Eve. Those are usually all gone by about 2 hours into the 11-month booking window.
Hard to get times include the first two weeks in December, New Years Eve, Spring break, all holiday periods.
Hard to get resorts include Standard view villas at BWV, Grand Villas at OKW, Studios in general, especially at BWV and BCV.
Just FYI.