In addition to signing driver packages, a Microsoft Authenticode signing certificate can be used to sign certain other types of files, such as executable (.exe) programs. Windows, especially Windows 8, does not trust unsigned executables as much as signed executables.  In Windows 8, an unsigned executable that has "no history" and has no reputation established with Microsoft will be treated as relatively untrustworthy, and is blocked from execution, unless the user manually overrides the operating system behavior, through an advanced options dialogue that is typically hard for new users to find. 

Additionally, some virus scanning applications also rely on executable signatures, to help establish relative trustworthiness.  In some cases, unsigned executables, free of  malware/viruses, can still be blocked from execution by the virus scanning software, until a history/reputation is built up establishing the executable as trustworthy.  Signing  the executable with a Microsoft Authenticode signing certificate will generally make the executable more trustworthy and less likely to be (incorrectly) flagged as malware.