Earlier quoted context omitted.
Cloud vs. datacenter is entirely about administration, rather than hardware.
I would say it's more about elasticity and the ability to scale horizontally if you take the minimum amount of precautions when designing your app.
This is what an engineer would say and that's important but, behind the scenes it's all about operating costs (e.g. administration). I worked with Cisco on a contract, they had about 22 folks managing the day to day operation for a specific on premise integration. Imagine if Cisco didn't have to pay 22 folks to manage the day to day? Let's say we cut that need in half but the licensing price remained the same or you could repurpose good engineers to deliver value elsewhere?
All of the elastic and horizontal stuff is great, but that's covered under SLA.