urlstyle, urlfont and newfontfamily interaction

I’m using XeLaTeX and fontspec. I want to change the font (to the courier font) that is shown when using url.

I don’t understand why "renewcommandUrlFont{courierfont}" works but "urlstyle{courierfont}" or "urlstyle{Courier}" don’t work. Using courierfont i get the error "!Missing endcsname inserted" and "!Extra endcsname".

output:

MWE:

documentclass[12pt]{article}

usepackage{fontspec}
usepackage{hyperref}

newfontfamily{courierfont}{Courier}

begin{document}
url{https://example.com/example}

urlstyle{courierfont}
url{https://example.com/example}

urlstyle{Courier}
url{https://example.com/example}

renewcommandUrlFont{courierfont}
url{https://example.com/example}

end{document}

documentclass[12pt]{article}

usepackage{fontspec}
usepackage{hyperref}

newfontfamily{courierfont}{Courier}
makeatletter
newcommand{url@courierstyle}{defUrlFont{courierfont}}
makeatother

begin{document}
url{https://example.com/example}

urlstyle{courier}
url{https://example.com/example}

end{document}