When you double down on the blackjack table or go all in during a game of Texas hold 'em, you're playing with real money. Only it doesn't feel that way, because you changed your cash into colorful little discs representing actual currency.
It's much easier to bet big with chips than actual money, and the losses don't sting as much, either. Many casinos also let you load money onto a card that can be used in digital games, providing yet another way to dissociate your gambling from spending real money.