A company I do work for has been doing a million+ or more in monthly credit card sales from iOS and android devices since '08. The iCloud Keychain didnt really increase numbers measurably at all.

When I started work for them I didn't believe so many people were willing to buy via mobile devices. Luckily, so was the competition, whom were not on their game and didnt want to accept such truths... so we ate their lunch. ;)