Looks like the cable is thin enough to be snipped by a cheap hand cutter in a few seconds, and I bet that lock can be opened in less than a minute after watching a couple of videos on YouTube.
Kensington locks have always been security theater. This is no exception.
Kensington has released a new accessory purpose-built for Apple's latest Mac mini. The Security Mount can also serve as a mounting bracket and even makes the mini-PC's infamous power button easier to access.