The reason is slaves needed a stick for rice - putting a chain between two stick sill works fine for rice work - but makes it a much worse weapon.
That reasoning makes no sense. There was no significant production of rice by slaves.
But also, threshing flails were used outside of rice-growing regions.
https://upload.wikimedia.org/wikipedia/commons/8/81/Battage_...
Considering that they must be hundreds of times more expensive than long sticks with no hinge, I would say the reason must be that they're better at threshing.
That reasoning makes no sense. There was no significant production of rice by slaves.
But also, threshing flails were used outside of rice-growing regions.
https://upload.wikimedia.org/wikipedia/commons/8/81/Battage_...
Considering that they must be hundreds of times more expensive than long sticks with no hinge, I would say the reason must be that they're better at threshing.