Although you have a valid point if we look at it from betting perspective but sometimes we bet just to have FUN and not the profits.
I do it sometimes just to see if I win the bet and ignore the odds. In such cases we can bet with extremely small amounts which are obviously affordable to lose.
I do the same, I only place small bets but it always gives me some thrill and excitement and it makes the games a lot more fun to watch when you place a bet on it. You won't become rich or loose a lot of money when you place these small bets so it is indeed just for fun!