A smash-and-grab on a retail unit is an opportunistic decision made in under a minute. The glass goes, they take what is reachable from the display and the till, and they are gone before the alarm response has finished dialling.
An 8-mil high-tensile layer bonded to the inside of the pane changes that. Struck, the glass breaks but stays in the frame, so getting through takes minutes of loud, visible work instead of seconds. For an opportunistic attempt, that is usually the whole decision.
What it does not do: make glass unbreakable, or replace your alarm. It buys time and noise, it never needs to be armed, and when a delivery reverses into the glass at nine at night, the pane holds and keeps the weather out until a glazier arrives.