Dice rolls are never random.
If you knew all necessary information (exact surface conditions, air resistance, rotating speed, ..) you could predict each roll with your dice. That's far away from being 'truly random'.
That's an extreme statement. You could say the same thing about Brownian motion. In the end, it doesn't really matter if it is truly random or not. The end justifies the means when it comes to an RNG.
Precisely.
You could also say the same about:
If you want to create the private key yourself (without any wallet), i'd suggest to boot up a live linux, let it run a few minutes, open and close random programs, and then use /dev/urandom to generate a private key:
openssl ecparam -genkey -name secp256k1 -rand /dev/urandom
Both are deterministic in the end, as long as you dig deep enough (but not so deep as to enter the quantum realm). The latter being obviously more practical than throwing dice.
As long as the result looks random to an outside observer, ie. does not show any bias towards certain numbers, you're golden. That is, as long as an adversary is unable to acquire the input required to (re)create the pseudo-random output. Which can be reasonably assumed for both physical dice and /dev/urandom.