I tried a before-and-after on the EFF Cover Your Tracks tool[0].
Before: One in 69970.67 browsers have the same fingerprint as yours. Currently, we estimate that your browser has a fingerprint that conveys 16.09 bits of identifying information.
After: One in 104957.5 browsers have the same fingerprint as yours. Currently, we estimate that your browser has a fingerprint that conveys 16.68 bits of identifying information.
So according to that, my browser is more fingerprintable after enabling the setting!
I didn't expect this experimental feature to be a silver bullet, but I certainly didn't expect it to make me more unique. I'm not sure what to think of that.