You know how you bought all of those silly Gamerpics and Xbox 360 themes because you would always unavoidably accumulate extra Microsoft Points after buying downloadable games? That's now a thing of the past. Gone are the dreadful days of forced 500-point increments!
Points can now be purchased in groups of 400, 800, 1600, and 4000, meaning you won't need to spend any more than you need to download full games.
Microsoft stealthily made this back-end switch sometime after Mega Man 10 released on Xbox LIVE Arcade (the last time I bought anything on Xbox LIVE), but we only just noticed the alteration. At any rate, I think Content Cat's expression sums it all up nicely.