Farmation of business messages contributing to the success of a business

I believe when business messages are sent or received, the organization is taken more seriously. Not only does it show professionalism, but it provides structure and allows the company and/or brand to be reliable. For example, if I am sending a professional email to a company to apply for a job, the employer would not consider me if my email is written like I am talking to a friend using slang terminology. I wouldn't even be considered because it is not showing professionalism. If I am not showing professionalism in my message, then why would the employer believe that I would be professional on the job? Just like if I am paying for a company to provide a service and they send me a business message, then I would be more likely to take them seriously and be more dependent on the company providing that service.