That's interesting, because I find #() rather less easy to parse compared to (comp) or (partial) for otherwise equivalent expressions.

At a glance I know that (comp f g h) and its flat list of arguments expresses a simple function composition chain. Seeing a #(f (g (h %))) where (comp) will do makes me sift through more parens; more than that though, when (comp) is embraced as convention, a #() is an immediate cue that simple function composition is not what's being expressed, which draws me in necessarily to examine the particular structure of the #() body.

A happy medium IMO is to give the function resulting from `partial` or `comp` a name in a let binding. If it takes one arg, great; if it doesn't then the #() form with the named fn inside still a little shorter & easier to parse. This is inline with the other advice that brevity isn't the main virtue for readability.

Exactly. The author wasn't advising against using higher order functions in general, just certain ones like comp and partial, which are easily replaced by anonymous functions. I.e. (comp a b) is the same as #(a (b %)), so why not use the latter if it's easier to understand. I don't completely agree with the author on this point, but I know he wasn't against higher order functions.