Nothing beats real life. But. But I think the photo below is worth a 1000 words to answer why paint realistically. Life is fleeting. I know this from my heart. To capture life, that's an endeavor. Not just so I can see it, remember it and get it but so that other's can get it too. There's room for unrealistic visions but it starts with the real thing. The undistorted beauty of real life.
Some will say, "Just take a photo." That's valid. Except there's something about someone's touch especially when they interpret the soul of other with their own. Nature's soul (or Human) to Human soul. And nothing shows it more than original art. Photos are lovely, as are prints of original art. But. But to see the strokes, shadows, saturation of color, the life - there's the soul to soul of real life.