Just a very brief suggestion. I think it might be a useful idea for the mobile app, regarding Pin Code Entry…
Some apps I have on my phone have the briefest (few ms) VIBRATE when entering key information, usually numbers and this I find gives (the user) great feedback at knowing what point the character is input and where your finger was when input - particularly useful for hidden characters also.
The benefit isn’t especially for confirmation of what you know you have pressed - more, it is an alert that you may have unwittingly pressed something you didn’t intend, and the vibrate indicates to you that something was pressed alerting the user to consider if a correct press was performed, before proceeding.
While not a critical requirement, and there is a 3 attempt before lock, I think this could be a useful addition for a future updates.