In Imperial Russia, stamps used on parcel cards and money transfer forms were often deliberately damaged before the cards and forms were sent to the archives. They had holes cut in them or pieces cut out from them and so on. Supposedly, the idea was to prevent fraudulent re-use of the (often high face-value) stamps though, actually, it was just a lot of work for very little gain.
The practice was continued after the 1917 Revolutions, notably in independent Ukraine where high volumes of formular cards were handled by post offices and regularly damaged after use. As a result, many of the stamps with Trident overprints which we encounter have holes or cuts - and from this, we infer that they have been soaked off formular cards by later dealers and collectors who got the cards when the archives were looted or officially sold off.
I have not met a collector who expects to pay the same price for a stamp with a punch hole as for a stamp without one. Some collectors won't even consider punch-holed stamps. But actually such stamps are an important source of information.
For example, many of the handstamped Tridents of Odessa (types 4 through 6) were or appear to be philatelic productions made for the benefit of big Odessa stamp dealers like Trachtenberg. I used to assume that the stamps with high catalogue values were generally limited editions produced for the stamp market. But, recently, looking at a mass of material from the Schmidt collection, I had to think again.
Look at these two stamps: