BitBTC should be
equal "nearly equal" in value to BTC. That is the promise of BitShares X. If this is the case, than BitShares X blockchain could act as the party responsible for automatic gateway between BTC and BitBTC. This can be done by BitShares X acting as the intermediary.
They might be "nearly equal" but they will never be exactly 1:1. One end of the trade will always take a small loss. It would require a market mechanism for buyers and sellers to agree on an trade (which is exactly what BTSX offers).
Regardless, I think that a precursor to this feature would be a BTC:bitBTC market. But I'm not sure if that's possible or worth it, partially for the following reason:
BitShares X would need to be able to act as Bitcoin client to receive/store/payout BTC on request.
This is kind of what I was getting at. BitSharesX would need to implement the BTC, LCT, DOGE, etc. wallets. And we would probably need to download their blockchains too. I'd rather avoid this bloat. This could possibly be avoided by requiring only delegates to have these wallets.
Say I have 1 BTC and want to trade you for bitBTC. I will need to send my BTC to an 'escrow' wallet that the BTSX blockchain controls. I can't send it to your BTC wallet in BTSX directly. Likewise, you would need to send your bitBTC to an intermediate wallet.
If this exchange is considered a transaction, then it sounds like a delegate will be responsible for releasing the funds. Once they determine we have delivered on our promises, they would move 1 bitBTC to my btsx wallet, and broadcast the transaction for my 1 BTC to your wallet.
There might be a counter-party risk there. I don't know.