Littoral advantages

[NFunky]

Well nobody anwered my other post, but I think this one might be a little more interesting to the community. It's a question again and one I've wondered about for a while.

What exactly are the advantages a diesel sub has in littoral waters, especially against surface ships? The only one I can think of is that it is more difficult, if not impossible, to use a towed array. In real life, medium-to-low frequency active sonars are more likely to blank out their own recievers, but this doesn't really seem to be the case in DW. With no layer, there is no way to move into the sonic shadow area and thus practically avoid active detection. Helos and ASW aircraft are just about as effective as they would be in deep water too, especially since I am forced to be closer to the surface and thus more vulnerable to MAD detection.

So really, why does everything I've read say that ASW is more difficult in littoral environments, particularly against non-nuclear subs?