Microservices scale differently to monolithic applications. In monoliths, the entire functionality is handled by a single process. Scaling the application means replicating this process across different machines. Such scaling doesn't take into account which of the functionalities are heavily used and which do not require additional resources.
With microservices, each functional element is handled as a separate service, which means a separate process. In order to scale a microservices-based application, only the parts that require more resources can be replicated to different machines. Such an approach makes it easier to better use the available resources.
