@tuatara1 i think in japan it's not the consumption, it's about the taste and appearance. their obsession with quality of food is what makes them special.
they farmed in special way, not only meat and fish, fruits and vegetables also. like those giant grapes, golden mangoes, white strawberry...
i think this is in part a calculated move from Uchimura, in part a desperation for money/resource. by keeping Butagalian alive for now, he can sell more rosemarine, the further he can travel, the higher the profit.