Although the earlier post regarding the mounting issues are true, using an iPhone as a Dashcam Recorder also brings some very nice advantages. Your footage is secure on your iPhone, nobody can view (find out where you live), steal or delete the videos. You can sync to the iCloud so you have unlimited storage and there is no need to copy files. These cheap "real" dash cams are not build to last and the video and battery capacity is really bad, especially compared to the iPhone. With the iPhone you could record in 4K

Another possible issue is the video format of these cheap dash cams, you have to make sure you can play it on macOS ...