You’re a marketer, a salesperson, not a writer.
Writing just isn’t your cuppa, you do it because you have to.
You need to get your point across, you want people to realise that you’re the real deal. They KNOW you’re not a professional language buff, so the occasional mistake won’t matter.
At all times, in business, you need to maintain a certain level of professionalism.
Your emails, social media posts, and blogs need to be both informative and accurate.
All of your outgoing messages should show that you deserve to be taken seriously.; and you can’t do that when your content is poorly written.