An rpm just needs to add the missing scripts and binaries to your existing operating system. It doesn’t need a full mini OS image to run. So an rpm will be ~2mb while a docker image of the same thing might be 150mb. Rpm and deb packages also usually contain startup scripts so any services can be set to start when your computer starts. And they can put log files and database files in your regular filesystem without any special nonsense. They run with (generally) user level access permissions, which are much more battle tested than root permissions through lxd. And they have full access to the computer’s networking devices.

Rpm/deb packages can also install man files, command line tools, gui apps, and so on that can run directly in your operating system.

I wouldn't say "intrinsically better". I have no idea what the One True Distribution Format looks like. I'd say at this point OS-level packaging provides more options and integrates better with the wider software ecosystem.

But let me ask you this: how often do you see:

FROM ubuntu:latest

RUN apt-get -y update && apt-get -y install ...

or the moral equivalent from a different distro?

And do you ever consider the idea of your stuff being incorporated into some other container?