What shapeshift says is that their prism is such a good product, that people will not mind paying these fees for holding it. We'll see soon if they are right or wrong.

and it only costs $5 to open, 1% per month in fees and $5+2,3% to close

QuoteIn short, its newest product, Prism, available today in closed beta, is less of an exchange and more a new way to trade cryptocurrencies, enabling users to create custom "prisms" by putting ether into a smart contract on the ethereum blockchain that is designed to mimic the price fluctuations of any of the hundreds of available cryptographic assets traded on exchanges.

http://www.coindesk.com/shapeshift-breaks-new-ground-prism-digital-asset-portfolio-product

Basically, you create a portfolio of different coins and shapeshift shorts it to you. You don't need to trust shapeshift, because your portfolio is secured by collateral in a smart contract, and you can settle it any time for ETH.