Nobody is immune to spelling and grammatical errors, not even me. It doesn't matter how many times you proofread your content, sometimes an error slips through the cracks. But, too many errors in your writing are bad for article writing services business and can also hurt your reputation over time. If customers are annoyed by poor grammar on social media or on a small blog post, just think about how they will feel if they receive an email or eBook laced with these errors.
And then there is the amount of time that it takes to create content with this software. I have had past experience with text spinners and although it might seem like a fast way to write content, it often isn’t! By the time you have chosen a piece of content (or multiple pieces of content to blend together), put it in the software and produced content with this software, you could instead have created content that Google loves.