What are usage rights and how do they work?
Why are they important?
Usage rights are the way in which an illustrator determines the cost of their work.
At their most basic, usage rights set parameters for illustrators and clients to work together and set a clear audience for the work and thus a price.
The way in which an illustrator’s artwork is used affects the cost of the work because the work can be used in a number of different ways and on multiple platforms.
A client may commission a piece of art for a set price but pay a much more affordable price if the work is not to be globally distributed. Vice versa, an illustrator should charge much more if their work will be seen internationally and used for multiple media platforms.
This link gives a different explanation of usage that might clear things up.