Okay, I quite often see people talk about child themes and the reasons for using them instead of modifying the existing theme, but they all seem to center around the idea that if the parent theme is updated all changes will be lost. When I've created sites in the past, I have always made a duplicate of the starting theme, changed the theme name in
style.css, and worked directly there. It seems to me that using a single theme instead of a child theme would save overhead, and allow greater control over the code - removing unnecessary functions rather than working around them, for example. If I run into issues, I always have the original theme files to reference, and if the parent theme is updated, my child theme could still break anyway if function names and such change, so I don't see that as a real benefit.
My web searches haven't turned up much on this topic save "developer preference", which is not really a reason.
Are there any real benefits of using a child theme over duplicating and renaming the theme?