The main function of softbox is to create even and diffused light. When we use the flash on our DSLR directly to our subject, the harsh line will be so obvious. So by using softbox we can bounch the light off a second surface to produce an even light on our subject. This two pictures taken strongly prove that by just having control on your light you can create amazing pictures.
ISO - 400 Shutter Speed - 1/160 Apeture - 5.6
Image taken with softbox.
ISO - 1600 Shutter Speed - 1/125 Apeture - 5.6
Soft Box was created in the tutorial class within 30mins. https://snapguide.com/guides/build-budget-soft-box-in-30-mins/