The rewards are great for feigning injury, a scorable free kick, getting a free out of defence despite being outnumbered, getting a player booked, wasting time near the end of a game, wasting time while a player is Black Carded.
On the other side referees will almost never punish anyone who tries this.
Thus making it a win-win situation for the cheater!
When anything bad comes into the game, Soccer is conveniently blamed. When you own up to your own shortcomings, you get closer to solving the problem.