I agree, if you take care of your car, you should never really need to jump start the battery. But, using this is probably cheaper than calling a tow truck to jump start your car, or towing it to a car mechanic to jump start your car. Tow truck, and car repair is very expensive in some places.
It is also probably safer to jump start your car yourself instead of asking a random stranger for a jump start because some strangers may be crazy, and attack people with a weapon.
