It's rather easy to trade cryptocurrencies in a decentralized manner. BTC goes into multisig, you receive the altcoin, BTC goes out of multisig. It only gets ha

It's rather easy to trade cryptocurrencies in a decentralized manner. BTC goes into multisig, you receive the altcoin, BTC goes out of multisig. It only gets hard when dealing in fiat. Nothing can stop people from falling into fraudulent schemes. Many altcoins are heavily premined, the developers are BS, or the developers have a disproportionately large upside compared to investors. But all of that should be apparent to all onlookers. The main problem I see with sidechains is that 51% attacking them is made easy by default. Unless you negotiate deals with huge mining pools, there's not enough security, and BTC can be stolen from sidechains if miners attack it. So the idea of sidechains looks dependent upon mining centralization which is a big enough issue already. I wholeheartedly agree with other posters. Blockchains just aren't good at certain use cases. You can't do HFT on a blockchain, even one with 10 second blocks. OTOH, the blockchain is censorship resistant and pseudonymous. In areas where excessive rules and regulations push out the little guy, the blockchain can be a solution.