Learning and passing on one's knowledge of CPR (Cardiopulmonary resuscitation) is extremely important.
Being trained is of primary importance. If someone with or near you goes into cardiac arrest (is having a heart attack), time is of the essence to get blood flowing immediately, not only to get the heart moving, but to get blood to the brain and other organs. Brain damage occurs very quickly when blood flow to the brain ceases. However, if CPR is administered and the heart begins to function once again, there may be no permanent damage at all.
Being trained in CPR can save the life of someone who might die otherwise...it could be a stranger or someone you love. And your actions can keep someone alive until paramedics or police arrive.
Secondly, passing on your knowledge of CPR, as a licensed trainer, I would assume, provides others with the same "gift of life" you have. Others can provide invaluable service when this kind of emergency takes place, and save lives. Emergencies are just that because they are not expected, and often times we are unprepared for them.
I can imagine nothing more frustrating—heartbreaking—than witnessing an event such as cardiac arrest and being one of many or all alone, without the ability to save a life. It does not take long, and I believe training is provided free of charge.