These really depend on the product. Kwoosh, the product in the article, is a team based project management tool and so requires a way to add other team members.
As for transactional emails, we have found that its the planning, writing, designing, producing content for them that takes time and not the actual sending process.
As for transactional emails, we have found that its the planning, writing, designing, producing content for them that takes time and not the actual sending process.