Chip+sign is a solution to a real market problem with chip+PIN in the US: the the typical consumer has many credit cards. https://www.quora.com/What-is-the-median-number-of-credit-ca... claims an average, not median, of 3.5 per cardholder, and that matches the numbers at http://www.creditcards.com/credit-card-news/ownership-statis... . Heavy credit card users have a lot more: it's common for stores to have store-brand cards that give you a discount at that store, so a number of people end up with a dozen different cards for stores they commonly shop at.

Expecting people to remember this many different PINs is not realistic. So every card issuer was worried that users would just stop using their card because they could not remember the PIN. This is the problem chip+sign is meant to solve.

In other countries, patterns of credit card use are quite different. http://www.theukcardsassociation.org.uk/wm_documents/UK%20Ca... page 6 claims an average of 2 cards for the UK, for example. So the "can't remember the PIN" problem was not as big a deal.