What is the difference between \maketitle and \titlepage in Beamer?

Question

I am looking for someone who has read the lengthy Beamer manual.

Using \maketitle

\begin{document}
\maketitle
\end{document}

versus using \titlepage

\begin{document}
\begin{frame}
\titlepage
\end{frame}
\end{document}

What is the difference between \maketitle and \titlepage in Beamer?

Answer 1

In beamerbasetitle.sty one finds

%
%
% The \maketitle command (for compatibility with other classes)
%
%
\def\maketitle{\ifbeamer@inframe\titlepage\else\frame{\titlepage}\fi}

and

\def\titlepage{\usebeamertemplate*{title page}\@thanks}

so \maketitle is basically \titlepage but adding a \frame if necessary, and it is provided for compatibility.

Answer 2

Only the second one allow you to use \includeonlyframes{current} keeping the title.

\begin{frame}[label=current]
\titlepage
\end{frame}