Any difference between \newcommand{\foo}{foo} and \newcommand{\foo}[0]{foo}?

Question

I have a co-author who defines many macros as e.g. \newcommand{\foo}[0]{foo}, explicitly giving the number of arguments even when it’s zero, where I have always previously used and seen \newcommand{\foo}{foo} for macros with no arguments.

Is there ever any possible difference in behaviour between the two versions, or any reason beyond readability to prefer one over the other?

Answer 1

there is no difference, in fact [0] is the default value for the optional argument so after the first scan for the optional argument they follow identical code paths.