On this video, photographer Daniel Norton from Adorama demonstrates some of the differences between hard and soft light for beauty shoots.
A soft (or hard) light has to do with the size of your subject compared to the size of your light source. The larger the light source compared to your subject the softer the light. For beauty shoots you might want (in some situations) a bit more harder light to shape the face in a nicer way (although on a subject with wrinkles might not look very nice) .
A softer light will give you less pronounced shadows while harder lights will tend to increase those and make them stronger – again this isn’t necessarily bad and it depends on the look your want to create in your image and the subject that you are shooting.
Norton starts with a large light source and moves to a smaller – harder light to show the differences. He did add some fill with the harder light to prevent the hard shadows which did change the feel of the image.
So you have (at least) two ways to create an image – soft light with a large light source or hard light (with or without fill) with a smaller punchier light source.