You can use GKE with a single node if it's big enough (it won't let you do it with the absolute smallest instance). I do it because I just like the k8s model for deploying apps. If any of my sideprojects deployed there ever start to matter I'll scale it up.
Whilst you could deploy k8s to a single node, it's massive overkill for that kind of solution.
The benefit I see in it is orchestration of large clusters of containers. The offset against that benefit is that there's quite a lot of complexity involved.
For single node solutions, if you want to use containers at all, I'd just use docker.