can anyone tell me looking at exchance rates why you get more if you have travellers checks instead of cash?

Answer 1

Because they are secure/guaranteed by AmEx. Less likely to be fraudulent and there is recourse when there is fraud.

In many countries if you deposit, say U.S. funds, that were in the form of personal check vs. cash in the same amount you will get a higher exchange rate.

To deposit/cash a check you must present some for of identification, for Amex you must countersign in front of cashier and match the signature already on the check and in many places you must also fork over some kind of ID. Most run-of-the-mill criminals won't go through that much trouble, so there are fewer instances of fraud with cheques.
With personal cheques they hold funds against the deposit until it's cleared by the originating bank and so they know that they are guaranteed payment.

Cash is "universal" tender and can change hands quickly and easily without raising warning bells. Whereas a check can only change hands so many times before fraud alert go off.

Answer 2

gtg