Well, Josh (of Dreamhost) would say - Get it before it goes negative so you don't have to give them bandwidth!
DH has had some bad press that the limits are so high that they can't possibly support everyone that signs up. In fact, many people refused to sign up because they thought it had to be a joke or that DH was a fly-by-night organization.
The idea is to gradually reduce the limits until people take them seriously again.
It's insane but people are paying attention. (We've heard that if you use a promo code they won't cut your limits.)
The most important thing to know is that DH bumps your disk and bandwidth limits every week. (How'd you like to get as much as 32G EXTRA bandwidth every week? I thought that that I had to stay within my extra before I was running out for months before I was able to confirm that I could use ALL of my bandwidth (I currently have almost 5000G) every month.)