German Military to be used inside the Country !

Germany had zero terroristic attacks the last years, and possible
threads where only media spectacle with no background.
So why would we need such a law ?
Even if a handful of "terrorists" would bomb a german city,
would we need armed troops to fight them ?
We have highly trained anti-terror police squads.
The only reason i can think of, is to fight civil unrest in
a case of a maybe upcoming collapse .....