Tesla—at least during the Delivery Event—is moving away from quoting battery size in kWh, preferring instead to focus on range. I think one reason for this (in addition to being more meaningful to most people) is that Tesla cars have more aerodynamic shapes and more efficient electronics. That means that a Tesla will go farther on a 50 kWh battery than a competitor would with a 60 kWh battery. After all, it's range that people primarily care about. So Tesla is in effect saying, "It's not the size of the battery, it's what you do with it."