Microservices are really one of the top buzzwords nowadays. It's easy to understand why: in a growing software industry where the amount of services, data, and users increases crazily, we really need a way to build and deliver faster, decoupled, and scalable solutions.
Why are microservices good? Why use them?
Actually, with growing demand, the need to deal with each module separately has increased. For example, in your customer application, maybe user information needs to be scaled in a different way from the address information.
In the monolith paradigm, you need to deal with it atomically: you build a cluster for the whole application or you scale up (or down) your entire host. The problem with this approach is that you can't focus your effort and resources on a specific feature, module, or function: you are always guided by what is needed at that moment...