Who is saying this? I think even Calle said ecash doesn't scale bitcoin. It does add privacy to custodial solutions.
Discussion
Yes, Calle is extremely clear that ecash doesn't actually scale Bitcoin, but somehow there are many who still think and say so
Not true. The anonymous credentials created in WabiSabi coinjoins can be used as a second layer: https://twitter.com/MrKukks/status/1619294643451199489