Docker's been around for a while (since 2010) but its widespread usage started just a few years ago with Kubernetes. Literally everyone is using it, that means it's a skill that companies want!
Containerization has marked a new era of microservice architecture. I used it and gotta say its some amazing stuff especially for a developer.
In most cases, college developers like me just focus on making the web app work and deploy it on was, Heroku, Azure, etc on a student dev pack or something else but forgot that companies have different needs and tend to, not use a PaaS (Platform as a Service) for deployment. They prioritize their specific needs and deploy on their own traditional server machines. PaaS like AWS hide this mess and regulate it at the same time ask a ton of money too For Example Apple spends 30 million on AWS per MONTH! no one wants that.
This is where docker and containerization specifically swoops in like superman and saves everyone. It gives developers so much power and scalability at their fingertips that most PaaS charge you for. try to use Docker and Kubernetes specifically. Kubernetes can scale to serve the app to thousands to millions of people. The Likes of IBM, Grubhub, box, Spotify, and a lot more companies use it.
If you've used Docker or Kubernetes flaunt it, if not just learn it. You will thank me later.