[Tex/LaTex] Using \textbf vs. \mathbf in Math mode

Question

Is there any preference for using \textbf or \mathbf in math mode; or \textbf works exactly the same as \mathbf in math mode? I know for example, the \textit does not work in some cases in math mode, e.g. $\textit{text1^{text2}}$ gives an error, but $\mathit{text1^{text2}}$ is valid. On the other hand, \textcolor is "usually" a better choice than \color in math mode [Ref: This post]

Answer 1

Spaces are ignored in the arguments of \mathbf and \mathit, but not in the arguments of \textbf and \textit.

Also, you can't combine \mathbf and \mathit. E.g., \mathbf{\mathit{xyz}} produces xyz rather than xyz.

And, of course, the outputs of \mathbf and \textbf will differ if you use different fonts for math-mode and text-mode material.

\documentclass{article}
\begin{document}
$\textbf{abc def}$ 

$\mathbf{abc def}$

$\textit{abc def}$

$\mathit{abc def}$
\end{document}