I've been using Docker swarm for internal & lightweight production workloads for 5+ years with zero issues. FD: it's a single node cluster on a reasonably powerful machine, but if anything, it's over-specced for what it does.
Which I guess makes it more than good enough for hobby stuff - I'm playing with a multi-node cluster in my homelab and it's also working fine.
I think Docker Swarm makes a lot of sense for situations where K8s is too heavyweight. "Heavyweight" either in resource consumption, or just being too complex for a simple use case.
The only problem is Docker Swarm is essentially abandonware after Docker was acquired by Mirantis in 2019. Core features still work but there is a ton of open issues and PRs which are ignored. It's fine if it works but no one cares if you found a bug or have ideas on how to improve something, even worse if you want to contribute.
Yep it's unfortunate, "it works for me" until it doesn't.
OTOH it's not a moving target. Docker historically has been quite infamous for that, we were talking about half-lives for features, as if they were unstable isotopes. It took initiatives like OCI to get things to settle.
K8s tries to solve the most complex problems, at the expense of leaving simple things stranded. If we had something like OCI for clustering, it would most likely take the same shape.
Which I guess makes it more than good enough for hobby stuff - I'm playing with a multi-node cluster in my homelab and it's also working fine.