Hi there,
the only time you MUST have a child theme is if you intend to make any edits to theme template files or write your own custom templates.
Other reasons when a child theme is good to have:
1. Writing lots of custom functions
2. Writing a hell of a lot of CSS
3. Adding folders to store local fonts.
If you have no intention of doing any of that then one is not necessary but no harm there being one installed in case you change your mind.