Nothing new. Charcoal has been used as an anti-fermentative, absorbent, or deodorizer in food for centuries if not millennia.
Charcoal biscuits (cookies) were popular in the late 19th century/early 20th century and were still around when I was a kid in the 1950s.
Charcoal is also used in Chinese cooking and that of of SE Asia.
What you are seeing is just the latest marketing fad.