For stone age tools it would have been less for the aesthetics and more for: what else are you going to use? You can use stone to hit stone, but depending on th

For stone age tools it would have been less for the aesthetics and more for: what else are you going to use? You can use stone to hit stone, but depending on the stones and the intent (and the technique), achieving the right results might be difficult or impossible. Other options: you don't have metal really. You could grind stuff, maybe, but that's a _lot_ of effort. So soft faced hammers should have had a place just by virtue of lack of other good options. My understanding is that for several things it'd be a lot of effort but relatively low technique required and relatively low risk of just cracking/smashing whatever you're trying to work on into uselessness.