There is an unwritten rule for selecting speakers:
what is your opinion on the web?
I think that a Code of Conduct or CoC is important for an event. If an event organiser with a CoC reads my blog posts about this subject, then there is less hesitation to select me as a speaker.
On the other hand statements on the web can have other consequences.
Most people tend to think about blogs. There are also social media. In the past speakers withdrew from conferences because of some tweets of/ about another speaker.
Another thing about having a blog is a proof that I am used and willing to share knowledge. I used this argument in job interviews.