While the panels are important, the main reason why its important to also have the battery component is because most people tend to work when daylight is out (where the house is theoretically using up the least amount of power) thus, if one didn’t have a battery, its pushing the power back into the grid. At the same time, power usage tends to spike when it gets closer to night, where solar is ineffective, and relies thus back on the grid if there’s no battery. While personally(not the original person) would never claim it does essentially nothing, the battery component is extremely critical for energy independence as the time period people want to minimize grid usage the most should be during the peak hours, which inconveniently is when the sun is down.
how the applicant thinks breaks down problems and handles how to answer them matters more than if the code is actually functional on the spot