From the Article:

"More businesses and nonprofits are moving their infrastructure to the cloud, now that it's proven to be secure, reliable and cost-effective. But while cloud service providers can improve efficiencies and provide benefits such as redundancy and the ability to scale up and down quickly, the cloud is not always the best choice or necessarily the least expensive."

This article discusses the factors that determine whether a workload is suitable for the public cloud, on-premises or private cloud.