I have only been riding with the power meter for a month or so, but it is more useful to me than all the other numbers I've gotten from bike computers over the years. In just a short time, it showed me (in numbers I could understand) when I was making my favorite mistake of pushing too much, for too long, too often. I figured out the range of watts that let me ride hour after hour. It's easy to punch up the watts beyond that range, but there's a cost for it. At last I have a way to budget the amount of energy I'm using while riding. I can splurge as long as I have a way of being an energy miser later in the ride. If I never get more out of having a power meter than this, it will be worth every dollar it cost.
I'm certain I will still go wildly pedaling down the road in the excitement of the chase, only to red line, fade, and struggle to manage the rest of the ride.
On the other hand, sometimes that isn't a mistake. It is just something you have to do in the pursuit of fun.