From the demonstration, it can be seen that if the angle is too large, it will still be exposed. Additionally, the clarity of the face swap is significantly different from the clarity of the original video. However, this thing is indeed very dangerous; it can be used to replace interviews in a simple way, and more seriously, it can be used for fraud.
Here is a demonstration video: Link to the video
Regarding the usage, you first select a face, then click on the live stream, and wait for about ten to thirty seconds. The live stream will have a delay of about ten to thirty seconds compared to the real video, depending on the hardware level.