Aligning your sales team's process to your marketing efforts to make the most of your time, marketing spend and campaigns. For example: collecting extra data in the sales process that affects how and when you nurture and message potential leads.
Getting members of your team to customise communications on a person by person basis is simply not feasible. By automating data capture, marketing emails can be tailored based on the data that you have about each customer (from name to browsing history). By helping you to market more and better, saving man power directly saves cost.
Big teams output lots of marketing and sales messages. Another factor of marketing automating is having the systems in place that ensure everyone's efforts are aligned and not conflicting. For example linking marketing to your customer relationship management system can ensure customers are only marketed to, using messages approved by their assigned account manager.