Jay Freeman skrev om det förut, skälet till att han skapade Cydia och inte bara använde Installer:
Why Not Installer?
One thing that I understand is that it is quite reasonable to question the decision to use Debian APT and write Cydia as opposed to just managing all of Telesphoreo's packages using Installer, which has become the canonical software distribution mechanism for the iPhone: Installer is the first, and often only, piece of software installed by virtually every automated jailbreak mechanism and is supported by a large number of repositories, each providing in the high tens of packages.
Unfortunately, Installer is not open source, and while there are plans for it to be so, there is no release schedule setup and the promise is getting stale. Cydia's source code is already available and other projects (such as MxTube) are benefiting from access. Hopefully, Cydia itself will soon be able to take advantage of this and begin to get third party patches and contributions.
Therefore, given the open nature of Telesphoreo, it makes no sense to rely on Installer in any central role. Even so, this has been the most controversial aspect of this project: many have asked why I felt the need to create a "new" application distribution system (porting APT) rather than using the existing, widely deployed solution. The fact that it will someday be open source is then cited as a reason to not "fork" the efforts of iPhone developers.
I feel the best response is simply to provide some perspective: Cydia/APT does not conflict with Installer. I run both on my phone and have a large amount of software installed via Installer. There are currently no known compatibility issues between applications that expect BSD Subsystem to be installed and devices running Telesphoreo, and no reason to suspect anything major on that front. Finally, no one is forcing anyone, packagers and users alike, to start using Cydia instead of Installer.