Bar soap is actually a lot better about moisturizing your body now than it used to be. It’s also a lot better for the environment and creates a significant less amount of plastic waste than liquid soap. And it tends to last longer than a bottle of liquid soap.
I’m sure you could use shampoo to wash everything. But it does have different moisturizers and oils and additives then soap for your body does. And that can make a significant difference to some people