The current maximum Argon2 settings are ridiculously quick on my mobile device. I would like to be able to increase the values further until I can reach my personal tolerable limit. Having significantly higher limits also allows the values to be easily increased in the future when devices used to login become quicker.
A popup warning when a setting value is increased greater than the current maximum value, and even another popup when the user hits “Change KDF” seems sufficient to cover accidental incidents.
For instance, “You have entered values that may cause significant delay in being able to login. Please double check the entered values before continuing.”