This model has been around for years to some degree, I have built out several server environments in Azure (MS) and always have to factor in the cost of CPU/Memory/Utilization and downtime as part of the overall cost, typically using
their calculator for more accurate estimates, AWS is this way as well.
It's the world we're moving into with cloud computing and Infrastructure as a Service (IaaS) but it also has its benefits, at the drop of a hat you can boost it to what you want with CPU, memory and disk space, you can also save during off peak times by lowering the power consumption or shutting it down. I can't speak to how this will be for average home users but for corporations it's completely shifted the landscape in just a few years.