Your code needs to run somewhere.
While you are developing you’re probably going to be on your local machine, but then when you want others to have access to your application you will have to deploy to a production server.
Having skills in this area is good so you understand the target environment and can work your way around it.
Developers that get good at deploying and maintaining environments (in the “cloud” or local) sometimes end up moving into DevOps (which I think used to be known as Systems Administrators a.k.a. root Gods)