[j-pb]

You obviously didn't read the article and jumped to the conclusion that they are talking about immutably peristent data structures, which they are not.

And even if they were talking about those (which they don't) your critique doesn't sound as smart as you seem to think if we just called them "lockless copy-on-write" data structures.

Lockless datastructures have some obvious advantages, and copy on write is one way to achieve that.