tvbcof, I agree with you that two days isn't out of the question for critical and high-value transactions, but Bitcoin main chain handles those perfectly well too, without the added cost and delay, and without security compromises. The competitive advantage of involving a sidechain specifically for critical or high value transactions is nil or negative.
Cripes smooth wtf happened to you? Has the real smooth been kidnapped?
Er. Anonymity? Hiding the value of that transaction with Blockstream's C.T.?
I've never been sold on that until and unless a sidechain becomes so popular that cypherdoc's fear of all the value being sucked out of the main chain and decoupling is realized, which makes the new chain just a replacement for Bitcoin, and again side chains don't continue to exist in a meaningful sense. (And obviously in that case my objection to failing to share Bitcoin's network effect doesn't exist either.)
In order to make that critical high-value transaction you are going to have to move a high volume of BTC to the sidechain, then perform the tranasction, then move the high-value back. Both sides of that will be not only visible but highly conspicuous on the Bitcoin blockchain. Neither you nor the recipient is likely to want to keep your high-value on a side chain for an indefinite period of time with worse security.