PEAR and PECL are great, but they add requirements to your application that live outside of the system.

You have to worry about your application being compatible with the version installed on the server and all sorts of other madness. Through this incredibly simple system (which will shortly become more powerful with its own interface) we can basically just install a package into your application in the same way most people would normally download, unzip, etc.

php oil install foo

Then add it to git, push and you're all good. Otherwise you have to run around installing dependencies and all sorts of other junk.