We booked & prepaid with a credit card, only to arrive after 12 hrs. of driving, to find that the hotel had NO record of our booking, & said they only use "xyz" service (NOT TRIVAGO). So, we hand no choice but to keep driving an additional two hours to find a vacancy at that late hour (1 am). We had to argue and argue, and wait almost three weeks, to get our money back. This is just a third party entity getting between you and your booking, AND gaining access to your credit card info. Dont bother.
SkinnyGina about trivago: Compare hotel prices, v3.1.1