Arcade sticks allow you to perform advanced motions with the joystick. In addition, you can perform simultaneous button presses with ease. Different button pressing techniques open up. One technique is pianoing, which involves hitting different buttons in rapid succession to produce a certain move. In addition, instant moves can be pulled off, such as landing a normal attack right after an airdash. Finally, there exists a technique which involves hitting two buttons almost simultaneously, resulting in techniques such as kara canceling and plinking.
Using an arcade stick is also helpful when dealing with nerves, which are common during tournaments or even heated sets with friends. Besides hands getting sweaty and slippery, using sweaty hands on a stick is much easier than with a pad. Also, it is harder to mish mash the buttons on a stick when in a nervous rut due to the buttons being more spaced out than on a pad. Thus, you are automatically more aware of each press.
It is always nice to be able to hit up any arcade and be comfortable with the type of controller present in the cabinet. It is true that you might be at your friend’s house and he or she might only have pad, but most stick veterans have had prior experience with pad before transitioning to stick and so pad would not be completely unfamiliar although it would definitely be a setback. Fortunately, it is not that hard to arrange bringing your stick with you to any session.