Is print in TikZ's math, useless?

Question

In the manual of TikZ 3.0.0, the section about the math library, we can read (p. 635):

Unlike the print keyword, the brace notation can be used in functions so that tikz path commands can be safely executed inside a tikzpicture.

And then there's this example:

\documentclass[tikz,border=7]{standalone}
\usetikzlibrary{math}
\usetikzlibrary{calc}
\begin{document}
  \begin{tikzpicture}
  \draw [help lines] grid (3,2);
  \tikzmath{
    coordinate \c;
    for \x in {0,10,...,360}{
      \c = (1.5cm, 1cm) + (\x:1cm and 0.5cm);
      { \fill (\c) circle [radius=1pt]; };
    };
  }
  \end{tikzpicture}
\end{document}

If I replace

{ \fill (\c) circle [radius=1pt]; }; 

by

print { \fill (\c) circle [radius=1pt]; };

I obtain exactly the same result:

This is probably because there is no function use. If we check with print inside a function that is inside a tikzpicture, we can see the difference.

\documentclass[tikz,border=7]{standalone}
\usetikzlibrary{math}
\begin{document}
  \begin{tikzpicture}
    \draw [help lines] grid (5,2);
    \tikzmath{
      function drawpoint(\s,\t){
        { \fill[red] (\s pt,\t pt) circle [radius=1pt] node[above]{(\s,\t)}; };
        print { \fill[blue] (\s pt,\t pt) circle [radius=1pt] node[below]{(\s,\t)}; };
      };
      coordinate \c; \c = (2cm, 1cm);
      drawpoint(\c);
    }
  \end{tikzpicture}
\end{document}

So my question is: Why do we need print ? Is there some example where we must put it?

Answer 1

The different between the print {some code or text}; and the {some code or text}; syntax is that the print keyword does not execute \nullfont inside a tikzpicture prior to executing its argument (or perform any checks to see if it necessary) making it marginally quicker.

Code inside functions is executed by the math parser which installs the prevailing font so that lengths such as 1ex and 2em can be evaluated. Thus, print should not be used inside functions unless extreme care is taken with spaces as they will be printed. The alternative { }; syntax can be used instead.

Additionally print is a kind of "syntactic sugar" to make code more readable.