Because with higher speeds, it returns to idle faster. 2G is also far less power efficient per byte. The most efficient phone using today's technology would b

Because with higher speeds, it returns to idle faster. 2G is also far less power efficient per byte. The most efficient phone using today's technology would be a category 10 or higher LTE modem /w no 2/3G modems at all. Radio is on for a very short time, then switches back off.