Deconstructing gives you materials needed to upgrade your shelter, or to build guns ,ammo ,or health
Been playing for a few hours and find that cars are the best source of loot, though its a bit buggy you have to find a sweet spot in order for the x to appear, also look for tool boxes or crates on the ground or on picnic tables, also the red tool boxes in garages are a good spot. Houses ive found just to be a waste of time you may not find anything in one.