A warranty is a useful tool to protect your solar system. Warranties may even cover you for damage not covered by your insurance company, such as mechanical breakdown and wear-and tear.
However, warranties are often limited in their scope of coverage. For example, your warranty may cover the cost of damage to panels, but may not cover the cost of installation. As well, your coverage may lapse when your warranty expires or if your solar provider goes out of business.
Together, your homeowners insurance and your solar system warranty work to protect your installation. When protected by your homeowners insurance, your solar panels are almost always protected for their full-replacement cost.