The descriptions have been around forever.
They are just used to describe the various conditions of the machines in relation to the money being asked.
It seems the descriptions are more important to those who have decided to pay a lot of money out for a brand new Pinny in or out of box, or for an expensive A condition machine regardless of year of manufacture.

Just a basic rating system.
Buy what u want. A machine for $500 can be as much fun to one owner that a $12,500 pinny is to another owner.
Buy and enjoy what you want ofcourse.
I have machines from $1200 to $12,000. They are all fun.