SCART is an abbreviation of the name of a European society of radio and TV manufacturers. The name is French and I can't recall the full form off the top of my head.
With so many separate input and output lines, a SCART connector is versatile. For instance, the red, green and blue picture information can be carried on separate lines, enabling greater bandwidth and better picture clarity.
But IMHO, like most European products and standards, it's overly complex. Maybe that's why it has never really been widely adopted. I have some European professional friends who say that they hate SCART