It's different for every visa office. But if you're applying through the Abu Dhabi office from the Middle East then it doesn't really matter if you apply online or paper. From the Abu Dhabi office they process online and paper in the same amount of time based on past posts on this forum.
If you need to provide biometrics you might as well submit on paper. When you submit online you have to wait for the biometrics request, honestly it doesn't take that long maybe few hours to a day. But if you submit on paper you can provide biometrics on the spot at VFS.