Sometimes things are made later that should be watched earlier (ie. Kenshin OAV1 before TV, TV before OAV2, movie sometime during TV[not exactly sure]) and (Bebop movie after ep 23)
Sure it's not going to kill the watcher if they watch them out of order, but its nice to know when to watch what, especially with an old tv show (ranma) with multiple movies and OAV's
So it'd be nice to not have to search around for these things. I know at least some people at AR are concerned about this, due to the view order.html that was included with Evangelion.
AniDB RULES!
View order list for anime confusing seasons [DENIED/NO REQ]
Moderator: AniDB