Yes it is convenient, and does track a subject, but not always your subject. For this reason, I always use one-shot.

In situations where there are multiple potential subjects, but one I wish to focus on, one-shot is really the only way that works for me. In sports, but even in travel photography: In sports, you are shooting a soccer game, and you wish to focus on your daughter. With players moving all around, the camera very often will instead choose a player moving toward you, rather that your preferred subject. With travel, you want to take a photo of your traveling companion in a busy square. The camera my initially focus on your companion, but then changes focus to a moving person nearby.

When I am not trying to focus on a specific subject, AI Servo is fine. For example in Auto racing: if I want one specific car in focus, I will use One-shot, and a single focus point, panning to ensure I keep focus on the one car. If I simply want a shot of the action, I will move to AI Servo and shoot away, with the assurance that I have focus on something.