that depends on the card and the speed control. some of the cheaper speed controls offer no programability, so no card, others offer more programability if you use the card instead of the throttle stick on the radio. some are so convoluted to program using the throttle that you will lose your mind if you don't use the card.
my preferred speed controls don't use cards, but the manufacturer has windows software that allows you to program even more features than a card does.
i use the castle creations mamba micro or sidewinder micro for any scale model i care about. they are much more expensive than the speed controls you can buy at hobbyking, but i feel they are well worth it. (you can find the sidewinder micro for $50 to $55) to use the software, you need to get a special usb adapter that plugs into the speed controller. ($20) I like them because you can do all kinds of things like set an exponential curve to the throttle, allowing for a low speed bias, with the throttle stick being more sensitive towards neutral. you can also set them to have no "stutter" between forward and reverse. lastly, if your motor spins too fast at maximum speed, you can reduce the actual output to a percentage of true potential in single digit increments (so, if 90% of true output is what you want, 90% of true maximum can be set) because i have model submarines that in real life run extremely slow, i have used the speed control to use only 30% of the maximum power.... another way to limit your maximum rpm at the prop.
if you do buy a cheap speed control that offers programming via a card, the cards are generally less than $10, which makes them better to have than not have.