Perhaps you define "dubious" as "anything outside one's normal paths" (or my paths, if I take you literally), but I don't. You'll note that your proposed usage doesn't actually work. It failing to work is not caused because I haven't personally tried that failing experiment.

In order for your usage to work, you'd have to break less dubious usages that are already working (as well as making Perl less efficient).

Note that you can also make $object->() work via overloading of a less-dubious object.