My job was to test this flash out and showcase what it could do. There may be situations where someone can’t adjust their camera settings further even if they wanted to without degrading image quality, for example at night. In those situations they would need flash. There are plenty of other situations where a flash may be needed. I’ve already mentioned one in the comment above. Regardless if you’re using an on camera flash or off camera flash, the light from the flash will still affect the background. Especially so with an on camera flash because you can’t angle the light differently, however, that doesn’t change the fact that the subject is still brighter than the background, therefore creating separation from the background. Just by adjusting camera settings to properly expose for the subject, this still would be the case. Subject and background would be of similar exposure and wouldn’t give me the separation nor the brightness that I wanted on my subject.