According to developer Oberheide who made these apps, they where there purely to test the security of the Android market. The developer claims to also have found out that Google can also remotely install apps on Android devices.
The method used for remote installs is called install_asset. According to Oberheide, this method is a serious flaw in the OS security as man-in-the-middle attacks could be carried out toward Android devices. For those interested in the full technical details of this, check out his blog.