> This idea has been successfully used by likes of android chromeOS and such to create seamless and risk free updates.

Those are not updates, they are just containers deployments at the end of the day (Flatpak and all related technologies).

> your normal distro does updates by pulling every package on your system and swapping files mid running this can cause miriad of issues just by doing it and another miriad if update is stopped mid updating(not always but sometimes). So this means your system is being recomposed at runtime

In practice rolling distros so that every day, with very little issues. (Arch is a good example of that).