Software architecture has changed a lot with the advent of "the cloud" - which IMO, is just a marketing term for the hybrid of the pre-existing internet and distributed computing. This sort of highly distributed and complex architecture (i.e. microservices) has seemingly become a standard for or at least a mild-expectation of all new applications. In order to wrangle the complexity introduced by an architecture built for 99.9999% uptime and infinite scalability you'll need to learn some tools to help you along the way.
Now, do you need all those things for your app? I think you'll definitely need to know UNIX to a reasonable degree, but all the other stuff (Docker, Ansible, Terraform, CircleCI, Kubernetes, etc. etc.) are just specialized tools for helping alleviate some effort in deployment and infrastructure management.
Start small and use what you want / need.
devops is important because developers tend to know best the requirements / quirks of their application. If you have it running on your laptop it shouldn't be too hard to get it running on a remote server. I'd assert, much easier for the developer of the app than for an ops specialist with no knowledge of the app that they're deploying.
devops can be as simple as a bash script.