There can also be old images with e.g. old openssl versions being used. Its not a concern if they are updated frequently, but still manual.

It can pull and build containers fine but last time I tried there were some differences. Mounts were not usable because user uid/gid behave quite differently. Tools like portainer dont work on podman containers. I havent tried out any networking or advanced stuff yet.

But i found that the considerations to write docker files are quite different for podman.