Nothing wrong with it. She's happy to feel safe and loved with her dad, and he gets to be the man keeping his daughter safe from bad guys out there while spending time together. I'm sure they respect boundaries with her dating, etc, and I'm sure he doesn't mind her friends going nuts over her dad, with one of the best physiques in the world. At the same time, he can bail and be a grownup and meet people, as can she.
If you're not together 24/7, it could be a very good idea for family vacation as an adult.