Why would potential customers needs to discuss about the production techniques

Maybe they are posing as customers in order to gain industrial intelligence. l have done that, myself.

The customer is probably savvy about costs vs. quality.
They want to ensure that they r getting the best product at the lowest price. It is important that the production operation is efficient & well engineered. They also expect that the final product will meet their expectations.
Of course, the real answer is dependent on the industry. like if it is
Making surfboards.are they handmade or machined?
Electronics.clean environment, testing requirements
Food industry..possibility of cross-contamination, packaging etc.