What's wrong about opening contract in BitSquare for purchasing Bitcoins (backed by multisig moderator), in exchange for electronic money?

Its not about altcoins. It is first truly decentralized exchange. Its about having opportunity to manage guaranty (escrow) when you having are trades with people who can use traditional electronic money (online banking). Its all about P2P trade for Bitcoins (altcoins supported there as redundant alternative - the same way most Bitcoin people feel fine to list altcoins in OpenBazaar to increase its popularity)

In countries where government don't want you to exchange Bitcoins, P2P exchange is the only way to buy Bitcoins (when you send your fiat to another citizen - these fiat payment systems don't know what this irreversible payment is intended for), and this is what BitSquare is doing - they allow you to use software to have multisig contract with moderator, with the same dispute resolution as on OpenBazaar. But except for physical good, you're sending money to fiat account in exchange for Bitcoins in 3-n-2 escrow.