The option to buy back with Ethereum seems more reasonable than paying for campaign participants with Ethereum.
of course paying with ETH is always easier and more convinient than other altcoins, it would be great if ICOs pay it by ETH but there are many cases that the amount of money we recieved by ETH is so little that it is not worthy for us bounty hunters use their time in those ICOs bounty, i still think accepting the risk to be paid by ICOs token rather than ICOs because it still have the chance to rise double or tripple the value of token when we sell.