What are the diffences and are there drawbacks involved in replacing `\setmainfont{erewhon}` by `\usepackage{erewon}`?

In the first case there is no bold small caps, but there are in the second. This is a serious advantage, but are there any drawbacks?

Should one use `\usepackage{erewon}` without optional arguments? If so, should it be loaded after or before?
It makes apparently no differences to the mwe output.

```
\documentclass{article}

    \RequirePackage{fontspec}
%       \setmainfont{Erewhon}[
%           Extension=.otf,
%           UprightFont=*-Regular,
%           ItalicFont=*-Italic,
%           BoldFont=*-Bold,
%           BoldItalicFont=*-BoldItalic,
%           SlantedFont=*-RegularSlanted,
%           BoldSlantedFont=*-BoldSlanted,
%           SmallCapsFont=*-Regular,
%           SmallCapsFeatures={Letters=SmallCaps}
%           ]

% or
\usepackage{erewhon}

 \setsansfont{texgyreheros}[
        Scale=MatchLowercase,% or MatchUppercase
        Extension=.otf,
        UprightFont=*-regular,
        ItalicFont=*-italic,
        BoldFont=*-bold,
        BoldItalicFont=*-bolditalic,
        ]

\begin{document}

\textbf{Exercice}

\textbf{\textsc{Exercice}}

\textsc{\textbf{Exercice}}

\textbf{\scshape Exercice}

\textbf{\textsl{Exercice}}

\textbf{\textit{Exercice}}

\textsc{Exercice}

\end{document}

```