This ZIP file does not have a KERNEL in it, it is just a ZIP with empty boot and system folder. The META-INF contains a script that will copy everything in boot to your \boot in your ROM and everything in system to your \system in your ROM.
NOTE: It will overwrite any files that have the same file name in the same folder. So, yes, you can use it for other than updating kernel, say copying a file to a specific folder in \system partition, or \boot partition.
Just open with 7-zip, drop zImage file into the boot folder, then drop modules in the system\lib\modules folder. Copy the zip file to your SD, then run Clockwork Recovery, and install the zip.