Why is this important for me?

Specifying your rate range makes it easier for clients to consider working with you. If you establish your rate range, you will not be bothered with notifications for jobs below your minimums. You will also be able to compare your rates with aggregated data from other pros working in your language pairs

Also, by specifying the range in which you are willing to work, you supply valuable information that will be used in educating clients. For example, if a client wants to post a job at 0.001 cents per word (a very low rate), he or she will be presented with data showing the percentage of pros who are not willing to work at that rate. This helps to head off unreasonable offers.