How are these better than jumper cables?
I buy one and toss it in the car. 5 years later when I need a jump start, it's dead/discharged and therefore useless.
I buy one and keep it plugged in at home. Some time later when I need jump start away from home, it's not with me and therefore useless.
I buy one and keep it plugged into the car. 5 years later when I need a jump start, it's dead from all the charge/discharge and heat/cool cycles it's been through and therefore useless.
I buy one and toss it in the car. 5 years later when I need a jump start, it's dead/discharged and therefore useless.
I buy one and keep it plugged in at home. Some time later when I need jump start away from home, it's not with me and therefore useless.
I buy one and keep it plugged into the car. 5 years later when I need a jump start, it's dead from all the charge/discharge and heat/cool cycles it's been through and therefore useless.