There are two ways to get the car fixed
Collision pays regardless of fault, subject to your deductible. Uninsured motorist property damage pays when an identified uninsured driver was at fault, typically with a much smaller deductible or none. Many drivers carry one and have never been told about the other.
It is cheaper and it is narrower
The cover costs less because it only applies in a specific situation: the other driver is identified and uninsured. It does not help if you were at fault, if the car hit a pole, or in many cases if the driver was never identified. For an older vehicle where collision is hard to justify, it can still be worth carrying.
An uninsured driver is a realistic outcome here
A meaningful share of drivers on any Arizona road are uninsured, and on a rural corridor the chance of being hit by one is not academic. This cover exists precisely because the responsible party frequently cannot pay.