No, that’s not just what flash is for. Take this image, made on a sunny day:
That was a flash image. Without flash, it would have looked like this:
Of course I could have just increased exposure *(lower “f”-number, or slower shutter, or higher ISO). But then, the entire image would have been brighter:
That’s not bad, but it doesn’t emphasize the subject, and I lose the opportunity to shape the subject.
So there are many shots where flash is not necessary per sé; it just increases the creative options available to you. Always carry flashes, is my motto: it makes my creative life easier by giving me more options.
Today, I host a Photographic Art Garage Sale at my home (scroll down). There is a very special deal on the e-books (http://learning.photography/collections/books) as well. 9AM-5PM: Come by if you are near Oakvillle, Ontario!