The traditional hierarchy of liquidity goes first cash, then Treasuries then checking accounts. Checking account balances (i.e. senior, registered claims on a bank) are junior to the first two (i.e. senior, registered claims on the U.S. Treasury and senior, unregistered claims on the Federal Reserve, respectively) for the reason you specified. I still contend a checking account will more reliably produce immediately-available funds quicker than a LN "deposit," even if one is a criminal.

This sidelines into why I believe illegal markets are the only place blockchains have a shot at being a currency. Shadow economies are substantial, between $1 and 3 trillion in the U.S. alone [1]. It's a different pitch from "replace the U.S. dollar," but it's more realistic. (I am not advocating anyone do anything illegal.)

Stepping back, it's pertinent to look at the Two Generals' Problem [2] which Satoshi's paper solved. It's a problem of exchanging information, not value per se. Blockchains are here to stay, but not--in my opinion--as currencies. Libor on a blockchain or legal documents "Docusigned" on a blockchain are far more compelling than "we'll make our light-speed payments system less reversible and better for illegal activity". They're also use cases which become difficult to justify if the "tokens" underlying them rise in value.

[1] http://www.imf.org/en/Publications/WP/Issues/2018/01/25/Shad... Table 4, page 11

[2] https://en.wikipedia.org/wiki/Two_Generals%27_Problem