>Credit Cards were introduced as a less-secure-but-more-convenient-check.
Yeah, no. Diners Club was the first credit card and was released in the 1950's to aggregate and streamline paying for things on account. It was, as the name suggests a line of credit. Checking accounts could become credit accounts if they allow overdrafts but this is not the normal intent.
It was not until First National of Seattle released a debit card (also now known as a check card) in 1978 that any of those plastic cards behaved as a check.
It's an important distinction because in one case (credit) the money transferred first is the bank's. This has important implications on who holds the liability and how long investigstions take into fraud allegations.
Chip security was added first overseas because online authorization was less ubiquitous. The US was able to have online terminals pretty much everywhere since the 1980's and knucklebusters became a rare sight in the 1990's. The chip security now is less to prevent card-present fraud in the US, more to prevent reauthorizations of stored CC information (see, target breach). With a chip or NFC the card generates a unique signature for every transaction so there's nothing a POS system could store to reauthorize future transactions.
This is why in the US for credit cards a pin is mostly unheard of and we are finally moving away from signatures which have been obsolete since the time offline batching mostly went away.
Edit: Consider 1980's America was under the monopoly of AT&T. This greatly influenced the design of payment card networks. Europe, for example, probably had probably over 100 different companies in dozens of countries, so universal online authorization was less feasible.