Did you look at the last 2 pictures? The cracks almost reached the outside.
I cannot believe that you cant feel them. They are almost a millimeter wide.
Yeah Germany, the country with the 1/3 death rate in traffic, compared to USA.
Indeed, you would not be allowed to run a car here with such discs (last 2 pictures).
But hey, its just about braking... Nothing important
Edit: But anyway: I'm a cautious person and would replace the replace the cracked one (i guess, they are the front discs).
And i dont want to argue with people, who may know better.
At the end, its your life you may play with. At least your car...
If you crash and have nothing else to worry about than the car, the insurance will try to find a reason not to pay. Discs with cracks (or exploded discs) look like a good reason to me.
I would not want to check the discs after/before every trip, but its my OPPINION.