not trying to mess with you, the code signing one makes sense to me, but what do you mean by 'apps connecting to their own home services'? and document signing? like DocuSign? how would an OV cert help there?
For documents, yes this includes things like DocuSign, but also signed PDFs, signed XML, etc. Any situation where a business, nonprofit, government agency, etc., is corporately attesting to something, like the signing of a contract or the public release of a statement, can use an OV/EV certificate.