The math: it's around 0.9 cents per point, no matter the quantity. Marriott doesn't have a sliding scale for larger quantities.

In other words....pretty close to what the points are worth to me for regular everyday redemptions. So I feel no need to rush out and buy the max, but it's nice to know the option is there at a decent price if you need to top off a larger award.

Points buys are rarely intended to be a great deal...they're just a mechanism to get a few points in a pinch or to reset an activity clock.