I really think things like new business development and start-up branding have commonalities to what creative agency does during creative planning. (Although lots more are required like skills and knowledges about business, investment, market, technology and more importantly, ability to get things done.)
What makes a big difference are;
(1) Starting point is business strategy itself, not a client brief
(2) Escort from the inside of the organization and share development processes together to push the idea up for realization, not a back-and-forth correspondences of batches of information/proposals between a master-servant relationship (aka. client and agency), this is exactly why "accelerator" values!
(3) Final output is innovation or/and business itself, not limited to creatives.
Although I need more study and learnings, this is so much fun!