It's just a matter of success and failure; once it fails, you won't finance again. But if the person is winning, that would help you earn consistent profit, provided he sticks with the same setup.
That's how a gambler should think. It shouldn't complicate things. We're all in this to expect two possible outcomes: either we lose or we win. Similarly, when trusting a person, it's akin to a gamble with agreed-upon terms. If they succeed, we win; if they fail, we lose. It's that simple, right?
Yes, it's that simple. But the problem is if he loses and he can't pay back the money he borrowed from us, what do we do? I guess people who lend money to someone will collect the money, right? Unless he actually gave the money and it wasn't a loan. If so, the person does not have to return the money, whatever the outcome. But most people will ask for their money back and they don't want to know what happens to the borrower because that is the risk of people borrowing money from other people. Besides that, we also have to think about how much money we want to borrow or how much money we have to finance that person. We cannot fund someone with a large amount of money.
I think borrowing/lending and investing are two different aspects although very similar.
If you are lending some money to a friend or a person, you don't care what they do with it and what they bet on, as long as they have a way to pay it back.
When you are investing in a player you are accepting that the person might fail and trusting his abilities to win. In that case, if he loses then you have to just accept it and move on.
I've never funded a player but I have tailed sports bets from experienced guys and gave them a tip when it hit.