Italicize "et al." while using style=authoryear with biblatex

Question

LaTeX code is:

\documentclass{article}
\usepackage[style=authoryear]{biblatex}
\addbibresource{biblatex-examples.bib}
\begin{document}
Read \textcite{cotton}.
\printbibliography
\end{document}

Output is:

    Read Cotton et al. (1999).

References

Cotton, Frank Albert et al. (1999). Advanced inorganic chemistry. 6th ed. Chich- ester: Wiley.

I need to italicize et al. in citation and references. So I did this:

\documentclass{article}
\usepackage[style=authoryear]{biblatex}
\DefineBibliographyStrings{english}{andothers = {\em et\addabbrvspace al\adddot}}
\addbibresource{biblatex-examples.bib}
\begin{document}
Read \textcite{cotton}.
\printbibliography
\end{document}

Now output is:

Read Cotton et al. (1999).

References

Cotton, Frank Albert et al. (1999). Advanced inorganic chemistry. 6th ed. Chich- ester: Wiley.

Is \DefineBibliographyStrings{english}{andothers = {\em et\addabbrvspace al\adddot}} a good solution to this problem?

Answer 1

It does the job. Conceptually, I'm not too fond of adding formatting markup like \em and friends into bibstrings, but in this case it could be argued that italicising is part of the orthography.

Personally, I prefer the solution using bibstring formatting sets explained in my answer to How do I get "et al." to appear in italics when using \textcite or \citeauthor with biblatex, but of course purely code-wise it is longer than just changing the bibstring.

\documentclass{article}
\usepackage[style=authoryear]{biblatex}
\DefineBibliographyExtras{english}{%
  \DeclareBibstringSet{latin}{andothers,ibidem}%
  \DeclareBibstringSetFormat{latin}{\mkbibemph{#1}}%
}
\UndefineBibliographyExtras{english}{%
  \UndeclareBibstringSet{latin}%
}
\addbibresource{biblatex-examples.bib}
\begin{document}
Read \textcite{cotton}.
\printbibliography
\end{document}

This also italicises the Latin "ibidem".