The 12 must haves were the outcome of a customers and partners survey on technologically important things. How did a commercial point make it onto the list?

It's the economy, stupid!
Actually this nice property of the NG firewall offering is responsible for a lot of real-world security improvements.

Consider an organisation with 2500 Users in 70 locations.
All web security subscriptions (Anti-Malware, URL Filter) are purchased as site licences. This means, they pay for 2500 users, regardless, how they really access the internet.
If they go for 2 fat dedicated appliances in the datacenter or have NG firewalls in 5-10  locations doing the job or if they decide for having direct access in all 70 locations, it is exactly the same amount of money they spend.

Having such a scalable model, security experts are allowed to execute flexibly and to do the right things without taking care of internal cost allocation and the like.

This is why security technolgists rank this property among the 12 most important things in modern firewalling.