By way of example, a little over a decade ago a famous online streaming company used to upload all of their video masters for transcoding. This process involved a huge upload and a huge workload, followed by a significant drop in activity.
The problem was that AWS had to provision for peak usage instead of average usage. This resulted in a situation where the peak-to-average ratio was very high for just one or two customers.
To address this issue, the solution was to incentivize these customers to spread out their workload more evenly over time, at least until they were no longer the largest driver of peak/avg.
This is also why things like Reserved Instances and Spot Instances exist.