Hello! Great question. If you are using the canner to boiling water bath can foods then there should be no concerns as the food contents will not be in contact with the metal. If you are wanting to use the canner to prepare or cook other foods, particularly those with higher acid contents like fruits, fruit sauces, or tomatoes/tomato sauce then there could be concerns with the acid from the foods leaching compounds from the metal, particularly at the chip/rust sites.
Please let me know if that answers your question or if you have further questions or concerns.
Thank you for your clear and complete answer.