Packages make software installs and updates a lot easier. With packages, everything you install is atomic. If you have something like Abiword, that's in a package. When an update is available, you install the package for the new version. No "updates", no "patches". Just a whole new version.
That may seem like it could eat up a lot of bandwidth, right? But Linux distributions now use a system to reduce the update size. On Fedora Linux, that's done via yum-presto.
From the description:
Yum-presto is a plugin for yum that looks for deltarpms rather than rpms whenever they are available. This has the potential of saving a lot of bandwidth when downloading updates.But the key thing to remember is that you're still installing an rpm package. All that's changed is that you download a "diff" between one version and the next, and your system creates the rpm from the "diff". And you don't have to know anything about it to use yum-presto; it just there by default whenever you do an update.
A deltarpm is the difference between two rpms. If you already have foo-1.0 installed and foo-1.1 is available, yum-presto will download the deltarpm for foo-1.0 → 1.1 rather than the full foo-1.1 rpm, and then build the full foo-1.1 package from your installed foo-1.0 and the downloaded deltarpm.
Here's an example: I installed updates for my system yesterday, and (demonstrating the process for someone) happened to run the update from the command line. So I saw this message:
Presto reduced the update size by 77% (from 48 M to 12 M).
Rather than have to download 48 MB of packages to update, I only downloaded 12 MB. That saved me quite a bit of bandwidth - which is important, since I'm on vacation and the Internet connection here is very slow.