Simply because Adobe wish to add their update process to your computer startup process, and do the same with other Adobe services. This gives the rest of us in the real world having to hack startup using MSConFig to stop this happening, as modern fast computers don't need background services from third party vendors such as Adobe running until needed. Similarly you can check for updates for Adobe reader manually as and when you, not Adobe wish. It's basically very impolite of Adobe to use the shared dlls smokescreen nonsense! Also for Adobe to automatically add these entries to your computer startup without your by and leave or explicit permission!