Should I care about kWh and kW?
Maybe a little. You don't need to know the complete technical side of it. If you at least know the basics, you should be fine...
Kilowatt-hour (kWh) is how energy is measured. Like how much energy your battery will hold or how much energy your car's motor will use. The gas-engine comparison would be a gallon of gas. We charge by kWh, much like a gas station charges by gallon.
Kilowatt (kW) is how power is measured. For our purposes, this means "how fast" the energy is sent to your car's battery. The gas-engine equivalent would be gallons per minute. Just like a gas station doesn't charge by gallon per minute, we don't charge by kW. Why should you pay more for the same amount of energy just because your car is only taking it half as fast as the charger is offering it or clicking the gas nozzle to flow slower and not overflow the tank? Or if you're using a 60 kW DC Fast Charger instead of a 10.5 Level 2 charger?
Usage: "My car was charging at 47 kW and now I have 25 kWh which is more than enough to get me where I need to go."