My
SEO logic is: 1. There are many ranking factors and changing only one will have a little or no effect. For example if you never add or change content, do you believe that the crawl rate matters? 2. Of course, if the crawl rate is insufficient (not often enough) I don't think you can expect some better ranking. 3. I think the crawl rate should be natural (adequate) to your website. If your website tend to change the content daily, than it's right the craw rate to be also daily.
Anybody else? More opinions are welcome every time.