People take more risk on paper -- it's like your high school stock market contest where the winner put everything on a penny stock and got lucky. Will there be some bias like this?
No. It's not. It's really unrelated and a good idea. Wall Street S&P500 still beats Venture Capital returns on average and it has PLENTY of fantasy investing.
If most people on a fantasy site seem to be making money hand over fist then it's time to watch out. Angel investing is harder than most people think.