There are lots of establishments in Germany, be they small hotels, Pensionen, restaurants, train station eateries, etc where you show them your credit card you will be told that only cash is accepted. If you have not seen that or experienced it in Germany, you haven't traveled widely enough there.
I have seen this happen to Americans and other foreign tourists where upon presenting their credit card to pay, they're told to pay in cash. If they did not have the cash on hand, go out to the ATM. Likewise in Vienna at three restaurants I know of, if you want their names too, restaurants frequented by tourists and locals.
In Germany just because a certain establishment accepts plastic, that does not mean your plastic will be accepted...plain and simple. I'm referring to their accepting only the EuroCard, which only Germans have and is a MasterCard. That happened one time too in Dresden in 2009. I presented the MC to pay, was told only the EuroCard was valid. So, I paid in cash. The guy said no, ie. no use arguing even though MasterCard is the EuroCard. He'll refuse it.
Bottom line is relative to other European countries, Germany and Austria are countries where it is still a cash society. Germans have also told me as much.