I wanna tell you a story.
Way back when I first started on real radar, Honey Monster was talking to a Cessna 150 student solo one day; student called and said he had a rough running engine and was unable to maintain height, so he would have to land in a field. Honey Monster asked him if he'd tried carb heat - he hadn't so he tried it and surprise surprise, then engine started to regain power!
Now Honey M like me and many others had a PPL thus he knew all about carb heat; how many controllers have come throught the system now who don't know what it does; it certainly made a difference between a possibly bent C!50 and the aircraft landing safely.