Suitability for the task is one of the dialogue principles for user friendly design described in the standard ISO 9241-110.
Suitability for the task describes how reasonable something is in order to complete a specific task. For example, you could sweep the floor with a toothbrush. However, the toothbrush is not as suitable for the task, as a bigger brush would be much more appropriate for this task. When unnecessary interactions can be minimized or even completely avoided, something is considered suitable for the task.