Argon2 is pretty memory hungry. Recommended defaults go up to the gigabyte range. That means that you have to be careful that you don't create a situation where

Argon2 is pretty memory hungry. Recommended defaults go up to the gigabyte range. That means that you have to be careful that you don't create a situation where the user originally encrypts their passwords on a device with lots of memory but then tries to decrypt their passwords on a system with not as much memory as was used for Argon2. Then the Argon2 implementation blows up with an out of memory error and the user has effectively lost access to their passwords. Cache hardness might be more appropriate for situations where multiple devices are involved. Then the user just has to wait for a while if things go bad...