Why don't the World Government put every prisoner in seastone handcuffs?

[Warmmedown]

Seastone is supposedly the strongest substance, maybe even overall stronger than diamond. In that case, why do the WG even use non-seastone handcuffs, which leave open the possibility of escape by breaking or cutting (e.g. Tom and Franky from Water 7)?

You think that the handcuffs are that expensive? Or too heavy? Or could it be to protect marines who have DF powers (unlikely)?

Doffy had a whole factory that was externally built from seastone, so it's unlikely the WG can't afford it, unless it's really expensive to make it into handcuffs or coat handcuffs with it.

 

[Captain Cadaver]

Kairoseki wouldn't be needed for every prisoner, given not all of them are DF users, plus there's usually guards strong enough to take down most rebellious DF users such as Magellan and putting Kairoseki on mediocre DF users wouldn't be worth the Government's time. I imagine limited supplies would also be a factor. In regard to Doflamingo, he's a Shichibukai and a former Noble with a major hand in most underground trades, so he can likely get high quality products better than most facilities outside of the main three prisons.

 

[Warmmedown]

Cool, yep not every pirate is a DF user, but I would still slap seastone on everyone due to be executed and everyone with a bounty 50 million+, just so they can't break out of them with raw strength.