Aah Starlight! What a question!
There was a time, when they first came out, that I thought, since they would be rare, I would frame them. My wife allowed me to place the first three Chinese New Year sheets on the hallway wall. Then she asked, "So, how many of these are there going to be?"
Um... the answer was not 12, as we know, but 24 for just the New Year's. The number is 55, now.
Here's what it looks like now: (updated photo previous posted)

At the left are the sad four framed New Years press sheets, which cost more to frame than to buy (at the time).
I can't think of what
Canada Post has in mind for them - other than for investment purposes. The USPS has a lot more than Canada, with both perforated and unperforated versions.
Those of us infected with the collector virus can't help ourselves. All I can say is thank God I don't collect USA.
One last note: it is instructive to find that many "press sheets" are not the real press sheets! Prove lies with the Titanic issue, where errors are found on the press sheets but none ever in the issued souvenir sheets that were cut from them.
(Hmmmm - unless the whole top row was thrown away...)
Has anyone ever seen a real press sheet that is different that the offered one?
I'm sorry that no one else answered your question, but, you see, it reveals a dark secret in the heart of every serious Canadian collector!