In TeX/LaTeX's default mode, there is extra space after sentence-ending periods, which needs to be suppressed with \@. when TeX would mistakenly treat it as ending a sentence, as in Mr\@. Bean. While \frenchspacing eliminates the (nominally) double space between sentences, I wonder if sentence-ending periods are nevertheless treated differently from abbreviation periods (e.g., when stretching spaces, computing penalties, or whatever).
In other words: If I use \frenchspacing (and will never format my text without it), is there any point to writing \@.?
\@does not suppress the extra space but actually enforces it AFAIK. You would writeMr.\ Beanto suppress it. – stefanct Mar 13 '17 at 11:58