Got it! You need to pay btc and receive eth. I thought you were looking for normal eth mixer. For WW I don't really know how they mix I never read the Ann nor used any mixer before thus yes mixers can do better.
As far as I understood the announcement, there will be a fee involved for mixing through different currencies. In the beginning, whirlwind would have to provide liquidity on all chains to support the mixing but once user deposits on all different chains come in, they will have liquidity and the fees will keep the service alive.
This would drastically increase anonymity and being able to withdraw in multiple/different currencies makes the whole process flexible for the user.
We will have to wait for the release to be certain though, especially regarding the fees involved.
Sadly this thread is still being bombarded with spam