Comodo Digital Signatory tool

I’d like to see an easy to use application to sign files - either by the e-mail or Code Signing certificate. Currently, i see no reason why everyone must use command prompt utilities, such as Mono or the Signtool from WindowsSDK. Do programmers really afraid to create a real Win32/64 application for this purpose? What is behind this behavior?
I’m pretty sure Comodo can create an easy-to-use signing tool with a user friendly interface.

We can use some programs for signing purpose - e.g. OpenOffice and its own file type; PDF files signing under some PDF reader/writer applications etc. - , but this doesn’t include all file types. Why users can’t handle all supported files (e.g. dwg) from one application?