Absolutely, if someone has this real statistic of his own gambling activities then he will feel so bad to see the number of much money he had lost before.
Even if someone do gambling for fun only and lose small amount only every time he/she gamble but it can be a big amount if he/she count it in details.
This overall statistic may make us feel so bad and regret it, as we may think that "if I did not gamble, I'll still have xxxx money and I can use it for other better things"
thats why i see no reason why people need to tally their gambling expenses and winnings when they can just do it like a normal activities .
instead of counting our gambling money ?better to just consider it used for something funny and enjoyable.so if we win then that is another story.