How would you possibly know which fingerprints to trust? Also, do you honestly think there is any hope for the average user to understand what that means and know what to trust and what not to trust? IMO, that is a massive step backwards in usability, which directly impacts the overall security of a given solution. If something is not usable, then people will figure out a way around it and security then goes out the window.
For example, if users were responsible for knowing which fingerprints to trust for a given website, they would most likely just click "ok, trust it" for everything. Then, you're overall security goes way down because now people are conditioned to click "accept" to everything, regardless of the impact.