I love it! I searched for a "k9s but for docker" and found lazydocker and ctop. I went with ctop because it looks nice and I don't like terminal programs that use the mouse.
Can you explain why is it useful? I tried kubernetes-dashboard and lens but in the end I've found ordinary kubectl good enough for my needs.
for one you don't have to remember all the kubectl command names
for another it is much faster to do things, a couple abbreviated vi-like commands vs. long commandline args
k9s is great. JetBrains IDEs also come with a really good k8s (and docker) plugin.