Hah, you are German, as your interface reveals you. Me too. :)

You got me :)

What is the advantage of using this exchange? It is only good if you want ETH, right? Or are there other advantages as well?

Yeah so there are a few advantages actually. So first of all, as I said in the post, it works directly on the chain, so you don't need to deposit the DEC on to an exchange. What this also means is, you can build your own tools with their smart contracts, for example SL could implement that on their site. It's instant and it has pretty low fees.

I think it's mainly for people who use ETH anyway, but for them it a quick way to buy/sell DEC. Is there even any other Ethereum exchange where you can trade DEC?