Why was it important to keep the technology used to make porcelain a secret

Keep control of the highly valuable trade item.

Porcelain was a highly valuable item traded out of China. Keeping the process of creating porcelain secret meant China could maintain control over the product. This made porcelain highly valuable and a luxury item that the Chinese could market for high prices. Porcelain items were in demand from wealthy people around the world and they could only get those items from the Chinese who held the process secret. In exchange, the Chinese could demand a high price or valuable items from other places in the world.

It is important to keep the technology used to make porcelain a secret in order to monopolize and be the only provider of such products. Lesser competition enables the producer to make higher prizes due to the limited sources of porcelain. Also it is important for the one who make the porcelain because they we're many consumers in the market and this is their source of livelihood.