I think we're probably in agreement, but we're getting caught up on the definition of "piping".

In my case I'm using it to describe the use of a kernel pipe object. In your case, you are using it to describe the higher-level concept of connection from one processes stdout to another process's stdin (or something along those lines).

Repeating shawnz's comment more explicitly: you said that the mechanism used by <() is "not actually a pipe". What is `pipe:[20519634]` doing in the output of `cat <(ls -l /proc/self/fd/)`?

What it looks like is ls having its stdout (fd 1) directed to a pipe.

I think the point is that the directory listing is the same, not that cat supports both syntaxes.