You only need it if you want it. This config settings allows adding any EVA item to either first pod seat or all pod seats. Decide for yourself what you'd like to be added by default in every newly created pod in the editor. If answer is "none" then just ignore the setting. Normally, if you're going to do EVA construction you need at least one tool per pod and one EVA canister for every seat. Detach a part and drag-drop it into the container. Please, take a look at the manual, and