why there’s no need for distributions to use the same package format
The problem Bryan identifies affects third parties providing Linux applications directly to users: Bryan trying to provide his games to users of different distributions, or Google trying to provide Chrome, or Mozilla trying to provide Firefox, and so on and so forth.
If you’re one of those third parties, you can put your application in a package, or you can put it in a tarball.
If you put it in a package and provide a repository, your users can take advantage of the features of package management. Your app will show up in their package management applications, it will be updated when they do a system update, and a few other things. But there’s a problem: different distributions use different package formats. So if you just do one package (and repository), you won’t be covering all your potential users. If you do RPM and DEB you’ll cover 90+% of them, but there are still a few who’ll be left out.