Germany is notorious for its wariness of cards and anything other than cash. I usually have about €200-300 on me.
Since the pandemic, people have been encouraged to avoid cash and many shops (especially the large chains) have enabled payment by phone, skipping the card system altogether (I am not happy with this and haven't enabled it yet).
But the thought of having less than €100 on me at any time is just not in the local mentality.
When I first moved here I remember being told that, as a foreigner, you are obliged to always have at least DM5.00 on you at all times. I have no idea if that was ever true, or if it still applies and what the minimum amount is these days.
I feel safer with cash than with a card. If cash is gone, it's gone and you can't lose any more and the thief has no connection to you. If your card is gone, the sluice gates are opened and anything can happen.