This might be a good example of the difference between a sportsbook and a casino.

A casino is pretty much a license to print money, unless there are some technical problems with the software or you are giving away too much in bonuses you will theoretically always make money whenever a customer makes a bet.

In a sportsbook you might have a great liquidity and a full department that actively manages the risk, but still lose money. If you are just copying the odds of someone else and don't do any risk management yourself you are just gambling, only with slightly better margins than the customers.

If you are investing in a sportsbook that you are not 100% sure is professionally run you are basically giving your money to somebody else and asking them to gamble with the money.