It is artificial, in the sense that the western twelve tone scale is essentially arbitrary (why not 6? why not 16?), and it is a constraint in the sense that what most people consider “in tune” is defined by what they’ve gotten used to hearing. Culturally, in western music, that is twelve notes to an octave.
People from all cultures can and do use notes from outside those twelve tones in music. In western music, sometimes you’ll notice (check out King Gizzard and the Lizard Wizard[1]), and sometimes you probably won’t (that “raspiness” in blues music is usually because they’re singing/playing a note slightly “out of tune” aka “microtonally”).
Music and “what sounds good” is a cultural construct, and I’d encourage you to check out music from around the world as well experimental microtonal artists if you’re interested in hearing what happens when you aren’t tied to the idea of twelve notes in an octave.