Some people can win a huge amount as jackpota but yet the amount that they won can not be compared to how much money they have lost in entire life while gambling, can you say such person has won the casino because they won a jackpot?
When someone win a jackpot at a casino, with a substantial amount, I'm sure they've won at the casino. There is no need to calculate how much they've spent during their gambling period. I'm sure gamblers wouldn't care too much about it.
Some gamblers may be overly careful about calculating their deposits and comparing them to their winnings. But if you're always counting, you might never enjoy your winnings, even if you win a large jackpot.