The reasoning we have for making a two-way pegged side-chain with Ethereum is that it will provide useful enhancements, (such as security, risk, and performance) and improve scalability, but only indirectly by enabling innovation.
The two way pegging allows for users on the network to send the tokens back and forth between the main-chain and the side-chain.
The side-chain will enable developers to safely develop new applications without risk.
There of course are some drawbacks to a side-chain, and there are also solutions that exist to mitigate these drawbacks.
We plan on hiring a developer(s) to accomplish these tasks, and once we have made progress on that front I will be sure to provide an update on this forum thread.
In the meantime, feel free to peruse these related articles and white paper:
Enabling Blockchain Innovations with Pegged Sidechains (whitepaper)
https://www.blockstream.com/sidechains.pdf
Announcing Sidechain Elements: Open source code and developer sidechains for advancing Bitcoin (blog entry)
https://blockstream.com/2015/06/08/714/
Are sidechains really new? at Bitcoin.SE
http://bitcoin.stackexchange.com/questions/24569/are-sidechains-really-new
How is a side-chain merging back to Bitcoin chain protected against double-spend? at Bitcoin.SE
http://bitcoin.stackexchange.com/q/24549/1652