Betting on sport events is somehow similar to stock trading: Complete amateurs can lose a lot of money, but for the expert, it's a serious source of income.
Because picking the right stocks can be tricky, a lot of people choose to buy fund shares and have an expert take care of their money. The obvious advantage is that someone can work on the stocks full-time, and due to the large amounts of money involved, any transaction generating even a small percentage is worthwhile.
I am sure that a true sports expert could do a similar job by placing money on sports bets: With enough time and experience, it would be possible to determine which bets - compared with the risk - have the best odds, and dividing the risk among many bets, the flow of profits could be rather continuous.
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