Containerization is beneficial from several angles:
Containers always behave in the same way, regardless of the environment — this means that staging and local development environments are often trivial to set up. And since containers are built using deterministic Docker files, configuration changes are now integrated in the normal code workflow — from code reviews and tests to CI/CD solutions.
The division of an app into different containers makes dependencies visible and components can be individually exchanged and scaled independently.
Containers are significantly more efficient than VMs — and therefore more resource-saving and cost-effective. In many cases, containerized apps achieve near-native performance.
Containers isolate the processes that run in them, both from the host system and from other containers — optionally also with private networks among each other. They thus offer simple tools to increase the security of the overall system.