Most people have taken some form of first aid class at some point in their lives. Additionally, many people take first aid courses regularly because their jobs require it, or simply because they want to keep their certification up to date.
First aid training is an important skill to have. It prepares you to take action in a variety of situations. If someone is choking on a piece of food, First Aid training prepares you to do the Heimlich maneuver. Or, if a person has a heart attack and stops breathing, you would utilize your First Aid training by doing CPR.
However, there are a different set of emergency circumstances that could require different training.