Sell the sizzle not the steak is an old marketing axiom. It means that people do not purchase a product. Rather they purchase an outcome or what the product can do for them. They buy the experience. In the case of the steak, they purchase the atmosphere, the smell, the sound, the taste and the way they feel when they are eating the steak.
Same thing with games. You don't purchase the game per se, you purchase an outcome or feeling that you want the game to provide. For example, look at Munchkin. I have never been so worng about the sales potential of a game. When Munchkin first came out, I remember thinking, "What is Steve Jackson Games doing? Two decks of cards and a rules sheet in a box 4 times the size of the contents. People are never going to pay $25 for this." (I also knew a lot less about marketing and consumer behavior back then). Needless to say, as I stare today at two shelves filled with Munchkin boxed games, supplements and additional paraphenalia, such as bobbleheads and dice, I have never made so erroneous a statement. Over a million total copies of Munchkin goodness sold say so.
Munchkin is a textbook example of selling the sizzle, not the steak. People are not buying the two decks of cards, rules sheet and box. They purchase the experience of playing the game, he fun of sitting around a table and getting silly with a group of friends or the hope they will successfully replicate the experience they had of playing the game with a different group of friends when they bring home their own copy.