Both Hugo and Netlify will tell you to use submodules when using themes.
That might work for some people but it didn’t work well for me and caused me to stop blogging for years because I didn’t want to/couldn’t figure out the conflicts with Hugo and various themes. Hugo releases come at a relentless pace and is backwards compatible for what seems like only a few versions.
When I was trying to update this blog, I ran into git problems with fetching the PaperMod theme as a SubModule. There were also warning messages from Hugo about PaperMod using deprecated language.
Right now those are warning messages but at some point the theme is going to break because it’s out-of-date. I don’t know when that’s going to happen and I don’t want to worry about it. So I pinned Hugo at the 1.60 version and cloned PaperMod so that I could edit the files and fix the issue.
At some point, I may want to upgrade Hugo or PaperMod or both but right now I just want a rock-solid blogging platform that doesn’t change without me knowing about it. And I have always wanted a static site so that I don’t have to worry about a WordPress vulnerability or one of their plugins being hijacked and my site full of spam or attacking other sites.