You are good at generating words and content. You have a great deal to share with the world (or at least your friends who are curious about what makes you tick).
Yes, lots of blog readers give writers a pass on spelling, grammar, and word choice. We give you the benefit of the doubt, and just read past the problems. But we would rather not have to. If your writing is unclear, it takes us longer to read it; at some point we may decide to pass on reading your posts because we just don’t have that much time. You want to keep your readers, don’t you?
Blog posts can be scheduled to publish when you want. Why not allow for a little lead time for a copy editor to give it a once-over review? This would give you a professional polish that others won’t bother with, so you will have an advantage.