I think escrow can't guarantee the investor to take part in ICO. Because I ever disappointed with another ICO, they escrow by someone with a good reputation.
Escrow just one way to make we are believe to this ICO, but not ensure success of ICO in the future.
Since qtum will sell tokens through bif and reputed exchanges, there is no need to use escrow.
i think people wants to get safe with their money so we can see that many ICO is use escrow. for ICO itself, they need to be trusted from the investor so they can make investing on that ICO. i hope this project will be succesful like other ICO and many investor will join with Qtum.