As I understand it, and I may be wrong, the power usage of DDR4 compared to LPDDR3 under load is not that much higher, but the standby mode power draw is a lot

As I understand it, and I may be wrong, the power usage of DDR4 compared to LPDDR3 under load is not that much higher, but the standby mode power draw is a lot higher, so the real reason is standby time and thinness. Anecdata: I have a 32 gb RAM laptop (thinkpad t460p) and battery life is excellent while actively but lightly using it, but I charge it every day so I don’t know what standby time is like. Also, while it is light and compact it is absolutely not thin.