Both leased and owned cars require insurance, with state minimums often including liability and possibly uninsured motorist coverage or personal injury protection. Leasing companies usually add their own requirements, such as comprehensive and collision insurance, and may also suggest gap insurance to cover any value discrepancies.
Lessees must purchase insurance for their leased car because it's not included. Not doing so could lead to penalties from the lessor or the imposition of force-placed insurance, which is often more expensive.