Pegged-value coins are very useful for me as they let me able to store wealth in an indeed stable, and decentralized way.
I'd never use tether due to their shady practices and they aren't much decentralized, they are just mean to be easily transferable between exchanges
I prefer coins like bitUSD or bitCNY which are backed by bitshares, usable in his decentralized exchange, and even start to be used by other exchanges like aex

I think it worth noting there is also other pegged-coins on the bitshares (bts) network, like bitGOLD and bitSILVER. A good way to invest into metals without having to store it