Because to some people using GUIs are more approachable and in some case objectively better (e.g. telling the state of things at a glance and efficiently using screen real estate, with graphs and whatnot), whereas the ways they're worse in might not dealbreakers (e.g. lack of automation, given that there can still be APIs or access to the underlying cluster anyways).
For an example of this, see pieces of software that one can use to manage orchestrators (essentially one step further than just running individual containers, but a good example of how UIs can be useful):
- Portainer: https://www.portainer.io/
- Rancher: https://www.rancher.com/products/rancher
Some orchestrators even include dashboards on their own:
- Kubernetes dashboard: https://kubernetes.io/docs/tasks/access-application-cluster/...
- Nomad web UI: https://developer.hashicorp.com/nomad/tutorials/web-ui
And some of that applies to running regular containers and managing them locally: for many it can be useful to be able to just click around to discover more details about a container, as well as what's using storage and so on. Thankfully the CLIs of Docker and competing runtimes are pretty well structured as they are, but I guess it's just a different type of UX.
At the end of the day, what works for you, or even what you find comfortable to use, might not be the case for someone else and vice versa. It's definitely nice to have that choice in the first place, and to know the various options out there.
