Well, sidechains will always be useful. Even if zerocash and ethereum were to be included in Bitcoin, we'd still use a playground for testing experimental featu

Well, sidechains will always be useful. Even if zerocash and ethereum were to be included in Bitcoin, we'd still use a playground for testing experimental features. When it comes to updating the Bitcoin protocol, there's a need to be very conservative and very cautious. The core dev team is working on a 2 billion-dollar running train over there. You wouldn't want to push changes too much. And even when sidechain support gets implemented back into Bitcoin, the sidechains will have to conform to a very specific standard. Otherwise bitcoin scripts will not work with them. On the other hand, sidechains based on distributed oracles ( like Orisi - http://github.com/orisi/wiki/wiki/Orisi-White-Paper http://github.com/orisi/wiki/wiki/Orisi-White-Paper ), can have any kind of form. If you want to make an alt-currency that sends you a chicken for each bitcoin you burn, and gives you back a bitcoin once you eat the chicken in front of the camera... You can do that with distributed oracles :)