system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is the point of cutting up cancelled credit cards?

Unfortunately, I got my wallet stolen, but I was able to retrieve it back two days later with nothing taken (yay). The only annoying thing was that I had to call all of my credit card companies to cancel my cards the moment I found my wallet missing and request new cards to replace them.

In the midst of disposing my cancelled cards, I was thinking to myself what is the point. The cards are cancelled, so wouldn't it be useless if someone were to copy the information off these cards anyways? The best thing they can copy is probably my name, but it's as generic as John Smith. 

I cut up all my old cards properly in the end, but I got curious: Is there a good, credit-threatening reason to cut up cancelled credit cards, since they are obsolete and shouldn't even work anymore?
gpt
It can be used to establish an identity, for one thing.  For example, a bank account requires two forms of I.D. (in the U.S).  A credit card with printed name is an acceptable secondary form of Identification.  Also, IIRC, the magnetic strip still contains the information on your account, and many identity thieves have machines that can read/manipulate the magnet strip.  The machines with the power to do so are sold on the free market.