...Though Most of the project are scam nowadays, if the bounty manager escrow the fund scammer does not get the more chance(but it will not stop). And to honest I have talked with some project team as a manager, when I ask about the escrow they don't agree with that. 
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...Depositing does not solve the problem of bounty payments if project tokens are deposited. Because if the team decides to close the project, such tokens will still not cost anything. It would be nice to Deposit a cryptocurrency such as bitcoin or ether, but I don't remember such cases recently.
Yeah. Bitcoin and eth payments can guarantee bounty hunters to get a good payment. If the bounty manager holds the token fund, it means that the bounty payment will be guaranteed. But if the project is scammed after the bounty, then there will be no benefit in getting the payment for that project. Because if that token is not listed on any exchange, Bounty hunters will not be able to sell their token even after receiving payment.
But that does not happen anyway any manager cannot accept payments with bitcoin and ether because it is difficult to find the bounty with escrow that has been provided and payments made in bitcoin.
Still, the bounty will be paid with the tokens they sell in the presale if it is not successful or fails to raise funds, but we do not receive valuable rewards, that is, the bounty now does not guarantee buyers with their tokens so it is certain that it will be difficult to produce better than the bounty