Not in the least. The CSSU is a collection of bug fixes and improvements to the software originally supplied by Nokia (and updated by their original "SSU" mechanism). Now that Nokia is gone, the community has stepped into the breach to continue this service.

Supporting the "thumb" commands in the CPU is an entirely separate project, which has nothing to do with supporting Nokia's software. There's no need for folks to install the thumb project in order to use the CSSU. So, it has its own separate thread.