Bank notes size and Costs

While I came to Europe for my studying I decided to collect monies of different countries both in Europe and of outside of Europe from my classmates with different nationalities.
Yesterday when I was looking at them and comparing them, I understood that there is huge difference in the size of these monies.This seems something usual and maybe we don't think that much about consequences of these differences but keep this in your mind and then think about two things.

1-Cost of printing bank notes will increase as you print a bigger one.This cost can emerge either from special print ink which has a security benefits or from special paper which again has some security materials inside.

2-As you have a bigger bank notes in your hand or wallet then the life cicle of them will decrease faster.

In my collection I found out that the size of bank notes in Uzbekistan, Iran and Ghana are enormous compare to many European countries and also China.
The reason that i bring these names as examples is that all of these countries have a high inflation and they are developing countries.
In Europe only 500 Euro is big in size but it rarely happens that somebody carry it for shopping or etc.In contrast in Iran everyone need 2000 Toman for shopping and daily usage and it rarely happens that you want 100 or 200 Toman.
I heard in the news few months ago that CBI have designed 5000 Toman bank notes which are wider and larger 2 or 3 millimeters in size.Now the question is that why we are still printing even a bigger size(not value) of bank notes when every year the officials are announcing a large number as the cost of reprinting new bank notes and destroying the old ones.
The only reason that i can think now is that the technology of printing bank noes is very old in there and the solution is buying new printing press machines.