What is the difference between the combination of split inside equation* and align*?

What is the difference between the combination of split inside equation* and align*?

\begin{equation*}
\begin{split}
A   &= B+C\\
&= X+Y
\end{split}
\end{equation*}

\begin{align*}
A   &= B+C\\
&= X+Y
\end{align*}
-