Your question can be split up into two parts:

1. Why should I containerize my deployment?

I hope by "deployment", you are referring to the backend services that serve your Android application; not the application itself (not sure how one would do that...). Here is a good article.

Containerization is a powerful abstraction that can help you manage both your code and environment. Setting up a container with the correct dependencies, utilities etc., and securing them is a lot of work, as is the case with any server setup. However, once you have packaged everything into a container, you can deploy said container multiple times and build on-top of it. The value of the grunt work that you have done in the past is therefore carried forward in your future deployments; conversely, so are the bugs... Additionally, you can also leverage the Docker ecosystem and build on various community contributions greatly accelerating your workflows.

A possible unintended advantage is also protection against configuration drift. Whenever services fail or your application crashes, you can simply restart your container, and a fresh version of the service will be created again. However, to support these operations, you need to ensure that your containerized service behaves nicely across restarts and fails gracefully. There are many other caveats and advantages that are not listed here; you can find more discussion on Google.

2. Why should I use Kubernetes for my container orchestration?
If you have many containers (think in the order of 100s), then using a single-node solution like Docker/docker-compose to manage them becomes tedious.

If only there was a tool to manage across multiple nodes, implement service discovery between your nodes, have fault tolerance (ie. automatic restarts, backoff policies), do health-checking of your services, manage storage assets, and conveniently expose your containers to the public. That tool is Kubernetes.

Here is a more in-depth intro.

Hope this helps!