Why 360 photo in Google Street View is supported only in phones with gyroscope?

I got few phone but all without gyroscope. In all of them, Street View app says: > 360 photo capture is not supported on this device. Why gyroscope is a must, are the gravity & compass not reliable to make 360 pictures? **Update:** Both gravity & compass have (x,y,z) components and I know both have some drawbacks: - gravity sensor is affected by acceleration (motion). - compass sensor is affected by metals and sometimes get locked is a direction. (move device in 8 path to free it). Also: - gyroscope has little drift with time (may not affect in this case) Anyway, are these enough reasons to drop phones without gyro from 360 photo capturing?