The greatest advantage some people really enjoy about an all inclusive resort is the 'carry nothing and worry about nothing' mentality.
Especially if you are traveling with children, in most all inclusive resorts you will find all your meals and snacks are included as well as soft drinks and alcoholic beverages. You wont need to carry a wallet or cash or anything else unless you want to... There are usually more than one type of restaurant to choose from and often if there are other resorts of the same group in the vicinity guests can use passes for their facilities as well. There are kids clubs with organized activities to keep children and teens safely occupied while the parents can have some free and private time to themselves (and isn't that a rarity this day and age).
It is a very convenient way to travel, worry free, and depends where you go is how much they will pamper you.