THANKS for the detail. I'm not opposed to its existence and use. It can even, and appropriately, use "BTC" in the name "L-BTC". Pegged one-to-one, I can see the validity of calling it a sidechain rather than a shitcoin. And development of such kind within the Bitcoin ecosystem is better (for Bitcoin) than it being built elsewhere.
But I still see that a government can mandate (or a situation may dictate) members of this federation to behave in a certain way. And even if the transactions are private, the fact is that it seems possible for transactions to get locked and for users to be "stuck" in the chain without being able to peg-out. With On-chain, you can run your own node and miner if you wish, and no one can stop a transaction from being included in a block.
As others have said, it has its uses. I don't see myself using it, but I'm open to learning more.
Also, I think with many of these technologies (even more so with chaumian mints), we may get blindsided by legal or regulatory issues. Bitcoin being the only real commodity (I have no idea how Eth is being considered to have that status), issuances of rights-to contracts ("money") and such are not the same as those for securities-- so much of the ado in the crypto space is a red herring in regards to how Bitcoin will be regulated.