Is it better to backup your iPhone to Finder or to iTunes? If so, why?

On Macs running Mojave or earlier, iTunes is the only option to backup on a iPhone on a Mac. On Macs running Catalina or later, Finder is the only option. The iTunes app was discontinued when Catalina was released. See: What happened to iTunes? - Apple Support

The backup is the same whether iTunes or Finder is used.

You can also backup an iPhone to iCloud. No computer is needed for that. See: How to back up your iPhone, iPad, and iPod touch with iCloud - Apple Support

I would just add that it is better to create multiple backups, i.e. backup both to iCloud and your computer, so that if you have an issue restoring one of your backups you might have a second to fall back on.

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