Glad you asked, @cyKopat! Smart Alerts will work together with your current motion preferences, and is designed to fine tune your motion notifications further. You are likely referring to this Help Center article, about refining your notifications with Smart Alerts.
While Smart Alerts work with your current motion settings and will not conflict with your motion zones, if Person detection is enabled on an externally powered device, you may not be able to adjust the Motion Sensitivity Slider.
Also, if it’s not clear whether a motion event contains people, due to lighting, weather, or other conditions, you may still see a motion alert in your Timeline. I hope this helps!