Using strobe lights for still photography is a very good way to learn about lighting, because one must “pre-visualize” or imagine what the effect of each light will be. We used to use a Polaroid to help visualize the effect, but now with digital cameras I suppose that is not necessary.
One of the great features of studio strobe lights is the ability to use a switch to control the power of each source; you can dial in full power, half power or quarter power. This is obviously much easier than physically modifying the output with scrimns or diffussion.
As regards the modeling lights, they are really just useful in an otherwise completely dark setting. There they can reveal the lighting contrast and overall effect to the eye, but when used in ambient light, they will not accurately show the effect of the powerful strobe light; here if anything they are most helpful in revealing reflections and highlights in objects with reflective surfaces (like eye glasses for example).
I would not recommend their use to light video though, because for the most part they are not of the intensity that would be required (especially when bounced into an umbrella or through a softbox.