I've only started using buttermilk in the last 2 or 3 years. Exactly as you do in my southern fried chicken. This is now a fave here. The whole family love it. But.... It is quite time consuming. As I'm the only cook here is why. A bit like croquettes, dredging takes time.We buy shelf and fridge stable buttermilk powder. I like chicken soaked in buttermilk either before dredging to fry or as a flavor enhancer for grilling some chicken pieces. The biscuits I like best call for buttermilk.
Apparently its very good in curry! I only came across that today and will definitely be trying it.As far as I am aware our local supermarkets do not stock buttermilk. "Tops" supermarket do stock some Waitrose produce (very expensive) but not buttermilk. We also have Tesco but it's branded "Tesco-Lotus" which is a Chinese run consortium. No buttermilk there either. It's not really surprising given the lactose intolerance of the majority of Asians. I suppose that I could make it myself but I've never really had the need.