# Why does amsmath define \mspace? \mskip seems fine and simple enough

amsmath.sty defines \mspace as follows:

\newcommand{\mspace}[1]{\mskip#1\relax}

What is the purpose of this definition?

amsmath.pdf says that \mspace is the "equivalent of \hspace for math mode use".

I know that LaTeX has a philosophy of using braces around every argument. Is that the point? Or is it the idea that \mskip is a TeX-command and thus shouldn't be used in LaTeX? I assume that the purpose of the \relax is to safeguard against a following plus or minus (for stretchable/shrinkable lengths). Is this explicit safety the purpose of the command?

Related:

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Yes, that's the point. I don't think there's much more to say. –  egreg Mar 4 at 8:26