Two key characteristics of the public cloud are scalability and the fact it’s a shared environment.
Scalability means that you can increase or decrease your capacity at will, without having to install new hardware. This means you don’t have to invest in expensive assets until you actually need them. You can also add or remove resources as needed, which allows you to scale up or down with ease.
A public cloud is also shared environment, meaning that many customers share the same resources. This is different from private clouds, which are dedicated to individual customers.