In my experience those sigils fell into the same trap that Hungarian notation discovered. A few sigils work well because they provide immediate comprehension,

In my experience those sigils fell into the same trap that Hungarian notation discovered. A few sigils work well because they provide immediate comprehension, but there's a tipping point where they become noise and a barrier because there's too many, in too many combinations, to be readily understood. In every perl script you end up reading them out loud to parse them. I remember the moment that Hungarian notation died for me (when previously I was all about it in C++): when I looked in the back of a Microsoft book on Visual Basic and found a six page table of four letter prefixes for all the different types you might encounter in VB6 with COM. The idea that I would either memorize those or continually look them up so that I knew what I was dealing with in code was the reductio ad absurdum of Hungarian notation.