Indeed, I certainly would not try resin for my 15mm.
It is slower to produce figures than a metal spin caster.
More expensive to produce and thus sell, in fact I seem to be seeing a lot of 28mm resin figures at around £10.00 each…
More prone to snapping of weapons and so on.
Plus any miscast resin is a waste, miscast metal goes back in the melting pot to be re-used.