You Just KNOW...
That having a blog (weblog) on your website can increase traffic.

You Just KNOW...
That having a blog can establish you as an expert in your field.

You Just KNOW...
That a blog can establish a COMMUNITY of visitors. Where each feels that they can participate in what you're trying to do.

BUT...

Follow up:

You also know that you barely have enough time as it is. For...

Doing the research...

Writing the draft...

Proofreading...

Editing...