Not sure what the terms of your comprehensive insurance are, but it sounds like it would be worth repairing it as it is out of the driver's line of sight. Ask your insurance company; mine pays for repairs because it avoids replacing the windshield.

The windshield can be replaced without problem; it is worth getting OEM glass instead of aftermarket, and make sure that the installer gives it time to set without driving it, usually overnight. The glass isn't special near the mirror, it is the same all over, but some non-OEM glass causes problems with the rain sensor.

__________________
2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue