

a serious attack helicopter
Chinook is a transport.
mobile interceptor
I am not sure what you are trying to intercept at a traveling speed of only ~300 km/h as a transport.
useful during peacetime for wildfire fighting, disaster response and search and rescue.
Not business of the Bundeswehr. Deployments of the Bundeswehr in the interior have restrictions unlike in many other nations. These tasks on a federal level fall to the THW. For the Bundeswehr to spring into action, the emergency has to be very specific, i.e., only the Bundeswehr has the necessary tools or be of such severity that the THW is overwhelmed as well.







My armchair general answer after a quick comparison of various transport helicopters on Wikipedia:
The Chinook is unmatched in its ability to lift cargo as a helicopter in Bundeswehr and NATO service. The NH90, which is the other transport helicopter the Bundeswehr operates, can lift ~5 tons of cargo. The Chinook can lift more than double the amount.
So this is a case of “We can buy American, or we can’t do the task”.