You can just take a picture of a pile of dice, a pile of rice, or a tree, patch of grass, etc, and compute a secure hash/whatever and base six it to get the rolls.
I actually have a lava lamp next to my desk for this reason. Snap a photo, compute a hash!
If you have a computer do something you cant know if it really did what you wanted.
Are you saying to take a hash of a picture and convert that to base 6 for your dice rolls to plug into a word list for creating a passphrase?
Is that actually better (in practice, not in terms of entropy) than /dev/urandom? I have a lot less trust in my ability to successfully scrub a picture from my phone that deterministically created my passphrase.