Hi, Beth!  There are many reasons to stay on-site at a Walt Disney World Resort hotel!  Yes, it is easier to get around because Disney will transport you anywhere you need to go (theme parks, water parks, Downtown Disney) for free.  If you are flying into Orlando International Airport, you can even be picked up there and taken to your Resort on the complimentary Magical Express.  However, my favorite perk for staying on-site are the Extra Magic Hours available to Walt Disney World Resort Guests.  It is the best way to maximize time in the parks!  The top-notch, incomparable Disney Guest Service is just the icing on the cake.  I'll run out of answer space before I can give you all the reasons to stay at Walt Disney World, so I'm linking you to the Resorts Benefits webpage.  Happy planning and have a Magical vacation!