Many posters have stated that the Nikon batteries last longer than 3rd party products for a single charge and the length of life of the battery.
LiON batteries store more energy than carbon zinc or alkaline and Lithium is far more reactive than many other metals. The purity of the chemicals can make a big difference in battery performance over their life. The electronics within the battery should prevent overloads from burning up the LiON battery. Nikon also included circuitry for measuring the battery life. When 3rd party batteries first appeared for the D200 many had the wrong electronic chips and could not power up the D200.
If you think a LiON battery cannot get hot or the quality of the electronic circuitry is not important just ask Boeing or find someone whose cell phone burst into flames or a laptop user who burned then legs. You will have to go back t0 2005 to locate articles about thi