At its end it was not used much for vector animation as it was used as for playing video on the web. But it had a reputation for being insecure, and for being

At its end it was not used much for vector animation as it was used as for playing video on the web. But it had a reputation for being insecure, and for being slow — because it retained the ability to put vector animation on top of videos. When HTML 5 was adopted with video playback tags (safer, faster, open), that killed it for web video.