It seems there's a bit of a misunderstanding about how containers work. Firstly, debugging in containers is not inherently more difficult than on a traditional system. You can indeed `tail -f /var/log/...` within a container just as you would on the host system. Tools like Docker provide commands like `docker exec` to run commands within a running container, making debugging straightforward.
The concept of separating runtime (X or Y) from data storage is not unique to containers; it's a best practice in software design called separation of concerns. This separation makes applications more modular, easier to scale, and allows for better resource optimization.
The "pull it again and run" mentality is a simplification. While containers do promote immutability, where if something goes wrong you can restart from a known good state, it's not the only way to troubleshoot issues. The idea is to have a consistent environment, but it doesn't prevent you from debugging or understanding the internals.
Lastly, while there are differences between application containers (like Docker) and system containers (like LXC), they both leverage Linux kernel features to provide isolation. It's more about the use case and preference than one being "real" and the other not.