Paying in some reasonable investment is an improvement, and in a world with different ‘right’ investments would be a bigger one, but tying up the money that long in a sufficiently safe investment is still pretty expensive.
It would be interesting if one could bet, say, shares of SPY US plus associated dividends, so you were leaking a lot less alpha. Of course, that changes the odds on long bets quite a bit if they are correlated with SPY US, which most of them will be.
Paying in some reasonable investment is an improvement, and in a world with different ‘right’ investments would be a bigger one, but tying up the money that long in a sufficiently safe investment is still pretty expensive.
It would be interesting if one could bet, say, shares of SPY US plus associated dividends, so you were leaking a lot less alpha. Of course, that changes the odds on long bets quite a bit if they are correlated with SPY US, which most of them will be.