Now, I'm not advocating copywriting while drunk, of course. But there is something to be said for letting the words come out naturally before you analyse the grammar, their meaning and purpose when editing.
When you don't censor the words as they flow out, you're far more likely to create content that engages the audience.
Having said that, editing is a crucial part of content marketing. By editing thoroughly - but still with respect to the tone of voice - you can create well-structured, SEO-friendly sentences that still speak volumes to your audience.