Because they use "herbs" which is why they're using the term herbalists instead.
Im a pharmacy student.. and history of pharmacy is way way back Ancient egypt... and of course, they use herbs as main source of medication.. but they are not called herbalists.. they are called apothecarist or pharmacists.. especially that the theme is on the royalty setting, pharmacist or the other name is fitting.. 薬ーyaku doesnt only mean herb but also medicine
Cause this is also a manga. Pharmacist is more based on a person that gives out prescribed medicine. Besides, if you've ever read any of the other mangas that deal with medicine the term hearbalisf is used more often in fairy tail like stories.
you think people care in a fantasy/fictional manga?
Nah , I just think the translators weren't sure what word to use. Shinkyuu is correct and that is the word usually used in high fantasy stories like that.
....why is it in the anime.. they used the word herbalist.... I think Pharmacist is a better term to be used coz ... thats what she does.. shes an apothecarist..