"It's also possible to get much better privacy and less transparency on layer 2+"
Agree, which is why an L2 on an encrypted base would be ideal for private and anonymous transactions. FCMP enables that.
"None of your criticisms appear severe enough to sacrifice the money part of money."
Fungibility is also a money part of money. A transparent crypto introduces more friction to that being an MoE even if you have an L2 on top.