Some bots are very much like human and some humans are very much like a bot.
lol
The reason Batoto did not choose to support download back when it started was because it gave an incentive for users to visit the scanlator sites. Since they almost always have a download link. After these years, I don't know how effective that has been, but that was the reason anyway.
Well, most of the times, it's because scanlation need some feedback (read:attention -- used to be on the similar business), either the reader give some comments or even chat on the irc. Some of scans, like to use n+x days before submit it on this site, though.
Last post, it's time to turn back into lurker.