Should one use fourier with erewhon?

Consider the following MWE.

documentclass[a4paper]{scrartcl}

usepackage{fourier} 
usepackage{erewhon}

begin{document}

This is my offer.

end{document}

The output looks as follows:

If instead one comments usepackage{erewhon}, one obtains this other result:

Look at the ff of the word ‘offer’. It’s obvious that they differ. Other than that, though, I haven’t found much difference between using fourier alone or fourier with erewhon (they’re just slightly, very slightly, different). Then, my question is three-fold:

1. What’s the case for fourier and the case for fourier plus erewhon?

2. Is this different ff intended or buggy?

3. If intended, which of the ff is typographically better, if any (and for what reasons)?

PS: the question comes from @egreg’s suggestion in her answer to this question, but I thought that asking this here could be useful to other fourier potential users.

Thank you all very much in advanced for your time.

usepackage[utopia]{newtxmath}
usepackage{erewhon}