If you hired a car and it wasn't available, you'd reasonably expect the car hire firm to sort it out and for you to not have to take out your own insurance to cover the failures of others.
So if the car hire firm was unable to supply a car because car hire was banned following an environmental disaster then they should be expected to look after you until car hire became permissible again? Well that's a lot less bother than worrying about old-fashioned travel and credit card insurance.
Life is becoming wonderful as our sense of entitlement rises to the point where our every setback is for someone else to wear.