[horsawlarway]

Cooling, lubrication, debris removal and dust control. Mostly in that order.

But yeah, you're completely right about the chisel. Hammer and chisel is how we've processed rocks for most of history (all the way back to flint knapping).

Wet processing for tile/stone is really only about 100 years old, since we didn't have a usable cutting abrasive until diamond blades came around in the late 1800s.

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All that aside, the problem with a hammer & chisel is that it's hard to be precise. It's not impossible, but it's definitely a skill requiring mastery.

If we expand the scope a little and include ceramics - then yes, we did need quite a bit of water.

Brick, Clay, Cement, etc - they were all good alternatives to chiseling stone to get a very hard, stone-like material in a very specific shape, and they all require good amounts of water.