Cooking a meal is more about tasting, technique than the exact amount of ingredients. Pastry is a different beast, it you don't use the exact amounts or time chances are your dish will fail.
Baking soda is a base, and reacts with buttermilk which is acidic.
It's not clear to me why some recipes contain both acid+baking soda and baking powder. Maybe they're worried that the first combination isn't sufficient?
My breakfast this morning used yoghurt + baking soda ;) (бухти)
There have been untold number of cooks who know nothing about actual chemistry beyond "water = H2O", including tons of professional chefs all over the world. In fact any chef before like early 20th century or so wouldn't know the first thing about chemistry proper unless they've studied chemistry -- heck chemistry became a real discipline after the 18th century, but exquisite cooking has been with us for millennia.
Parent said "understand food chemistry", which I understand not to be the chemistry of food as it relates to molecules and chemical reaction chains, but rather something more basic: this thing can soak too much oil, this burns quickly even in moderate fire, this food gets soggy if you put in this before that, and such things.
My mother studied food chemistry at college, so childhood baking generally included 20 seconds of explanation on why something I was about to do would make a mess. ("If you don't do X, the protein in won't coagulate and it will all fall apart.")
This mostly applied to baking, cooking eggs, or making a roux. The rest doesn't really matter.