The traditional way to install a package was to take an archive and then just extract the files off it into the required directories. This worked fine but then the administrator faced a problem when it came to updating the packages. He must locate the files from the previous install and then make sure they are removed from the system. RPM helps here. It is a easier and more flexible way of installation and maintainence of packages.
Upgrades are easy.
RPM maintains a database of the packages installed on your system as well as the locations of the files and the version numbers. Anytime you install a package in rpm format, RPM will check to see whether there are any files are in conflict between the packages installed and the packages being installed. It will also tell you whether any other packages need to be installed for the software to work. All in all RPM makes life a lot easier. RPM has become really popular and several distributions are now based on it.