Yes, ideally the tool should edit its own preferences. A quick and dirty tool might leave the user to run the macOS "defaults" command line utility themselves. It’s certainly no worse than looking up the dotfile format and firing up vi.
> It’s certainly no worse
It's much worse, you don't get persistent undo from previous edits, indication of current changed and committed data, syntax highlighting, regex search, etc, etc.
It's a lot worse, IMO. We're all fluent in our text editor of choice, we all know the rough format conventions of dot files.
Whereas I'd certainly have to lookup man page of the defaults tool, and IIRC it only supports editing one-key-at-a-time, which sucks for a dense config file.
If your tool provides a TUI/GUI for editing preferences, that'd be a different story.
Don't force your users to go through some custom sequence of CLI commands that they first have to spend 5 minutes learning. There should be no learning curve for a one-time setup.