Here is Firefox’s feature page for fingerprint blocking.

From what I understand about the specific setting you are referencing, the information typically used to build profiles is randomized each day.

My experience with fingerprint blocking in general has been cumbersome. The changes to time, window sizes, colors, etc., ultimately lowered the convenience and quality of life of my overall browsing experience.

I’m sure with the right setup, application, and mindset someone could find fingerprint blocking in it’s current form to be useful.