Hybrid IT

Capacity on Demand
When the ability to flex IT resource capacity is needed without long term commitments or if you lack immediate resources to scale up, implementing a hybrid strategy is advantageous. Both public and private clouds, including "everything-as-a-service" models (XaaS, EaaS), have matured enough to drastically reduce complexity.

You can maintain and provision resources while enabling scale up or down capacity within minutes. There is no upfront commitment to purchase capacity (over a baseline in the case of private clouds), it simply fluctuates as needs dictate. For example, if demand is seasonal and “bursty”, consider this model as an option, especially private cloud, which can be less costly for many workloads that are required to run 24/7 or most of the time.

Location
With hybrid IT, since a full commitment on all resources is not required in the public cloud (applications, data, virtual machines), sensitive data may remain on-premises if bound to certain regulations; or the goal is to reduce any exposure outside your primary network.

A tiered application could be beneficial if your application(s) need to be faster and accessible, closer to your own end-user customers, to empower their optimal experience.