As some members have already mentioned, this feature exists in Stake and other casinos. I myself have seen it in Stake, but I've rarely bothered to check it on my account. This is because I gamble very moderately, with small amounts that I can afford to lose, and I always gamble for fun, nothing more than that. So, at the end of the year, even if I went into the casino and saw how much I lost all year, I wouldn't be sad about the result.
That's why good bankroll management is crucial; it's a very important point. With good bankroll management, you define how much money you'll allocate to gambling each month, but only an amount you can afford to lose, and how to spend that monthly amount each day and week.
I don't allocate funds to spend on gambling per month, instead I do it the week I feel like gambling and it's only a tiny amount that I can use for about three to give sports betting. After it gets exhausted I wait till another week when I intend to gamble and before doing so, I must have had a rough idea of the main tournament or leagues and teams involved before funding my account to bet.
This makes the functionality of overall statistics on amount lost or gained quite irrelevant to me when I think I already feel content with just changing my bet strategies and sticking to small bet amount sizes.