I'm a CTO and I work closely with our CRO. In my experience, being involved in the sales process is an eye opener for a CTO. In early stage startups (heck, even in a billion dollar company), a CTO cannot be disconnected from sales. This allows help bridge gaps in product and how engineers think about product features. It also makes the CTO leave their ivory tower of technology and be more grounded to reality. I'll probably do a blog post on my experience some day