While you can absolutely create professional-level portraits with a single light, using multiple lights will allow you create more advanced and precise setups that simply are not possible with just one source. One of the most important secondary lights a portrait photographer can use is the kicker, and this great video tutorial will show you both what they are and how they are used to create more effective images.
Coming to you from John Gress, this excellent video tutorial will show you what kicker lights are and how photographers use them for portraiture work. Simply put, a kicker light is an accent light that helps to highlight the edges of the subject. While this can be a nice effect, they can actually be particularly crucial when working with a background that is close in color to the subject's hair, skin, or clothing. Without them, it can be difficult to distinguish where the subject ends and the background begins, but adding a kicker helps to separate them from the background. Check out the video above for the full rundown from Gress.
If you would like to continue learning about how to light a portrait, be sure to check out "Illuminating The Face: Lighting for Headshots and Portraits With Peter Hurley!"
I would respectfully disagree. You are right there are use cases where "classic" photography is not relevant anymore. But we just photographed some 50 people from a company with strobes. Technically that could have been done with an iPhone but the company wanted well lit photos from all employees..
If that is your hard & fast opinion, what are you even doing on this site?
85% of photography is understanding how light works and setting up the best possible circumstances for a good photo. Which kind of plastic box your sensor or film comes in only matters so far as it impacts the kind of photo you are trying to create.
Not a fan.