Seems that way alright. Tk seems to be popular on this particular forum, for whatever reason.
I suspect a couple of reasons why Win32::GUI may not be so popular, apart at all from the quality of the module, which I'm not in a position to comment on.
- The majority of Perl programmers are writing for *nix systems, so Win32::GUI isn't appropriate to what they're doing.
- A decent number of people writing Perl on Windows are at least aware of *nix systems, if not also using them themselves. These people are more likely to choose a GUI toolkit that's cross platform, so it can be run on multiple operating systems.
- People who solely run Windows get advice on GUI toolkits from the folks in the above groups and are led away from Win32::GUI, towards other solutions.