I think I’ve mostly said silly and fun rather than lighthearted.

But the basic idea is that they are at the same level of adventure, stakes and seriousness as most children’s movies. You wouldn’t call the Lion King a serious film would you? Even though it’s probably not light-hearted if you think about it. (Same is true for most children’s movies, think Land Before Time, most big Disney/Pixar classics etc.)

A more serious film, for example, probably grapples with Alderaan’s destruction and mentions it outside of two immediate reactions.