Achieving simplicity by glossing over details is distinct from achieving simplicity by stating something incorrect.
Which one is more appropriate and/or typical will probably depend on what questions the five-year-old is asking, but I think it's reasonable to say the former is usually preferable to the latter.
Which one is more appropriate and/or typical will probably depend on what questions the five-year-old is asking, but I think it's reasonable to say the former is usually preferable to the latter.