I know I hate it when I join IRC channels and have no context as to what anybody has been talking about, as there is no history to quickly go over. Even just having the past days history would help in this regard, at least for more active channels.

It's the same as just barging into a conversation a group of people are having. You don't want to just join and start talking about a completely different topic. So you join, and wait for a bit to get a feel for what they're talking about before piping in. But with IRC, sometimes it can take _days_ to get that amount of information, depending on how active the channel is. The same thing could easily be accomplished by being able to read the last 10 messages in the channel.