Insights

One of the more noticeable insights that occurs to people who follow politics, particularly the more cynical observers, is that things change anyway, so why bother.

To an extent I'd agree here. It is actually entirely rational for individuals not to care about the overall trends of political behavior in a democratic society, and to just go about their daily lives as peaceably as they may. Most political activity is in fact pointless. I'm having a hard time caring that much about this crazy lady who won the GOP primary in Delaware even though everyone in DC and NY seems to think its a sign of the apocalypse if some impending "miracle" would occur and she'd win the actual seat. Rand Paul potentially winning is a little more interesting, so would be Harry Reid losing in Nevada (to an equally crazy person), but this was kind of a non-story to me.

Still I do find a few reasons to care anyway about politics more generally
1) The political zeitgeist shifts can be sometimes directed into a single or narrower set of causes. This is a lot easier to do if there are people out there getting people worked up to perhaps change some stodgy policy (such as on gay rights or the drug war or previously on civil rights).
2) Most people are woefully uninformed about the varieties of ways that governments can already intrude on their daily lives or those of their neighbours or co-workers (among many, many other things political and economic). Giving them something they can see just how ridiculous it is may not change the underlying policy, but it might give people more cause to be aware of the pervasiveness of government policies and pay more attention, if not generally, at least to things they care about (schools, crime, taxes, etc).
3) Things change. But if you were part of the "team" pushing for it to change, you can feel like you helped accomplish something. If it's a change you'd want to see or you feel society would benefit from, that seems like a good thing. Even though things change, sometimes those changes seem momentous looking back and sometimes people look back and wonder what the big deal was. Either way, you'll probably be called upon to tell a story about it.
4) You will get more of the jokes on Stewart and Colbert if you've been paying even a modicum of attention. Also, more politicians and political figures will seem like idiots not worth your time and attention that way. In other words, paying attention to politics will make you just cynical enough to justify not paying attention to politics.