On the free version, you may encounter compression artifacts. Your final video might be lower resolution than the source, or the audio bitrate might be reduced. The "Premium" tier unlocks higher quality exports, which makes the "free" aspect feel a bit like a trial.
If a watermark is layered directly over a person’s face or critical action, 123Apps cannot “restore” what’s underneath. It will just blur the face. 123apps video watermark remover
Unlike local software, you must upload your video to the 123apps servers (even if the processing happens client-side). Uploading a 500MB video for a simple watermark removal is tedious compared to doing it locally on your hard drive. Processing times can also be slow on the free tier. On the free version, you may encounter compression artifacts