for now the only relevancy the isekaishit has is that he knew coffee and white porcelain exists (why does an administrative worker know how to make fine ceramic???). if the story would actually make him use his knowledge in a manner that's more deep than just being an encyclopedia this would...
You know what, I like that ending. It's literally just "and they lived happily ever after" but at least it's an ending as opposed to endless villain of the week shenanigans that isekais gravitate towards.