In fact, your financial institution is “locking up” collateral in order to make that iTunes micropayment work for you. That’s what a credit card is. So, LN micropayments are not that different, except you can do it without a bank by putting up the collateral yourself.
The analogy is from the user’s perspective, where it is different. In the current system, the payment is cheap and it does not lock them in. With the LN solution, the user must not only put down the collateral + network fees, but they are also now locked into that channel. With my credit card I can spend $0.69 with my VISA card on iTunes and then turn around and pay $0.42 on XBox Live with my MasterCard, and I still have not locked in any collateral.
Sure, the financial institutions have locked collateral, but that’s the price they pay for offering credit. If you can find a way to offer credit and less collateral to lock in using a blockchain, that would be a better comparison I think.
Also, thank you for engaging. I have tremendous respect for you and your work.