The researcher wanted to highlight the potential danger of these innocent looking cables and how a bad actor could take advantage of the innocuous nature. In his example, he modified a Lightning cable where he hid a chip inside of it that when plugged into a computer, can log the keystrokes of the user.
This means that while you think you’re charging your phone and going about your business, the cable could be stealing your data and key information like username and logins to your online accounts. He even made it so that the cable itself could create its own WiFi hotspot so that the hacker could connect to it and take the information off it.
The problem here is that the modifications are so small that it ends up being the same size as an authentic cable, which means that at a glance and unless you know what you’re looking for, it would be near impossible to tell. This only further demonstrates that if you want to buy a new accessory, then maybe go with an official one or one that’s been officially licensed, just to be safe.