Why do fansubbers merge video and subtitle into one file?
Sometimes its an mkv file and I can just extract the sub.
On some sites they hardcode it into the video frames as image overlay.
This is so silly. Why not just have the one video file which several languages or translation versions (corrections) can share, instead of re-encode and re-upload? And if someone wants a sub they can download just the sub. Distributing subs must also be easier because the subtitle files are smaller, so no wasted bandwidth, and it might not even be illegal to share just the sub. Plenty of reasons!
Do they have some reason which I do not realize?