This is another way to attract a lot of bounty hunter to support their idea for the bounty programme. But it is a guarantee that when they are listed on some markets, the project will be successful. And I doubt that this way will take a long time since the investor's confidence is that IEO / ICO will yield a huge profit in the short term, which means that they will always sell the coin / token when the exchange has started.
This is like a bounty that is paid with BTC because ETH is very liquid where bounty hunters can cash out their reward anytime and in any exchanges.
With this, it would also encourage investors to put their money since the business who runs bounty prove that they are capable and they have capital for marketing expenses and does not fully rely on the amount they'll raise.