A companion to Dry Stone Walling Across Canada
Two things occur to me; an unbonded wall allows slippage if there is settling of the bed and in a foundation or other load bearing wall it also means that point loads are transmitted straight down instead of spread over a wider base.
This is true except the more the wall begins to settle the more it tightens as it squeezes itself together laterally. I think stones laid flat in a wall are more likely to loosen and separate as they 'spread'
It looks like more work getting the stones to stay upright until you get the neighbouring stone in place. Some look like they are balanced on a point. Did you just wedge them?
They are all wedged but not on point.