Low rate cards offer low interest APR over a longer period of time. Unlike introductory 0% offers which are great if the debt can be cleared before the offer expires, these low standard rate cards are great if you will not be able to clear your balance in the offer period. In this circumstance a long term low APR card could be better for you.
One of the main advantages of low standard rate cards is that they do not shock you with a sudden rate rise in interest rate once the introductory period ends. In fact, with most of the cards, the interest rate remains the same throughout. Low rate cards are available with annual percentage rates starting at around 7% - this compares with the average standard rate which is about 18%.
If you are prepared to switch cards, then you can usually get a better deal elsewhere.