Theres nothing wrong with having a well written web site. More folks than you imagine will “bounce” from a site for lack of trust. You are judged on the quality of the words you use to describe your product or service. Uncorrected spelling errors and gross grammatical mistakes communicate that you don’t even care enough to turn on the spellcheck!
So aim high in your web writing tasks. Every business has someone, (usually a bad speller!) who’ll tell you that you’re a stickler for insisting on good grammar or correct spelling. They’ll claim that nobody cares, and they’ll be wrong.
Google doesn’t currently downgrade your site for grammar or spelling problems, but it could happen someday! Really. Dig a little deeper into your Google search results (Search tools >All results>Reading level) and you’ll find your search topic answers rated as basic, intermediate, or advanced. If Google can compute reading level, it could be a short hop to spelling and grammar.