the basis of my argument is that the BTC unit cannot be separated from its blockchain (mainchain) w/o breaking Bitcoin as Money. imo, sidechains allow this and if you read their whitepaper, their core assumption is that they they can be separated.

Blockstream registered as a for-profit entity earlier this year and they have $15M investment. their biz model is constructing SC's for other entities, namely corporations, banks, gvts, anyone willing to pay for the tech. in essence, they are now in the exact same position as Mastercoin, Bitshares, CP in terms of competing to mold Bitcoin into profitability for themselves.

their business model is dependent on inserting a change into the source code called a SPV proof. this would allow BTC to flow off the highly secure Bitcoin blockchain ledger into these SC businesses where sidechain ledgers rules will be determined however the business wants and will be inherently less secure as they will not be merge mined or even directly mined. they will require trust and will ensure security most likely by signing off on blocks as they are constructed with their own signing keys.

there will be thousand of entities who will bolt themselves onto Bitcoin via these SPV proofs. this will in effect allow a siphoning of value, BTC units, out of Bitcoin itself. how will Bitcoin miners make their required income from tx fees if all these BTC have moved offchain to sidechains? how will Bitcoin maintain its monetary function if all these BTC have moved to sidechains and have been converted to all manner of speculative assets?

Blockstream has every incentive to encourage this siphoning process. as a for profit beholden to investors, not only do they have an incentive, they have an obligation.