The issue with dashcam that works in parking mode is battery drain.
Most dashcams work by recording continuously. Those will create a drain on battery continuously, potentially leading to dead battery. So most parking mode change that to record only when motion is detected. The battery consumption on a continuously running motion sensor is significantly lower than a continuously running camera so that has potential to resolve the battery draining issue. However, the outcome is situational. A parking location that has no motion triggering event will be very different from a location that trigger motion detection 10 times an hour. Most people under-estimate how often the motion sensor goes off.
So one solution some dashcam setups come up with is it’s own dedicated battery (instead of using the car’s battery). When done properly, it won’t negatively affect your car. The worst thing that can happen is the dashcam battery runs out and the camera stops working until the battery is recharged. Again, that depends on all the issue mentioned above.