The NHL points system is a little... odd, to say the least.
I mean, you get points for losing. That's really all you have to say to question it. That doesn't make sense.
But it does create the interesting spectacle of three-point games, which contributes to intense playoff races. That's a large part of the justification for the system, and it's been going strong for several years now.
There's another points system that the NHL could adopt instead, though: three points for a win, two points for an overtime win, one point for a shootout win, and no points for a loss.