US credit card issuers also make more money: they keep 1.5-2% of the transaction and seduce you into 19-28%APR if you delay payments. The German/EU CC market is different: Mastercard only keeps 0.3% as interchange fee and the CC bill is decducted from your checkin account within 4 weeks.

So the benefits handed out are proportional to the income of the card issuing company.