Style matters. In life, the style of your clothes, your speech, and your car tend to say a lot about you as a person. Likewise, a business's writing style says a lot about its position in the industry, attention to detail, culture, and much more.
Keep in mind that we are talking style and not grammar. The rules of grammar apply to all users of a particular language. These rules cover things like subject-verb agreement and misplaced modifiers. No matter what your business uses as its style guide, it breaks grammatical rules at its own risk.