The use of Stellar does not limit the ZED in the ability to use other blockchains. ZED is built on top of Stellar platform with connectivity to BTC and ETH methods of payment.
And by partnering by Stellar for sure both of the teams which Stellar Team and Zed Team will make an amazing technologies which will provide an amazing transaction to all of us which is for more faster, secured and ofcourse less hassle and just a click away.