They do feed into a battery, usually in your garage, or you can sell it back to the grid. And they have a "lifetime" warranty. But the problems are: ridiculously high up-front costs (maybe 3x normal roofing), theres no such thing as a solar panel (or storage battery) that doesn't degrade over time and the "lifetime" warranty does not include installation labor, which is significantly more difficult than normal roofing installation.