Purpose of setting splitviewcontroller's delegate?



while going through this chapter, there are a few instances of setting the splitviewcontroller’s delegate, once even in the main ApplicationDelegate file. What is the main purpose of this, or more precisely, when happens if I omit doing this? At first, I thought that since for example the channelViewController will be sent the message [channelViewController listViewController:self handleObject:channel]; - that that is why we do it. However, when I commented out the part where it sets channelViewController as splitViewController’s delegate, everything still works as it was.

What am I missing here?