> True random number are slow. Fast PRNG are prone to collision.
Not in this decade. You can slam out a million securely random 128 bit numbers per second per core. For numbers you will store, the effort to store them is orders of magnitude greater than the effort to generate securely.
It depends.
True random number are slow. Fast PRNG are prone to collision. That's why we have different specs and versions of UUIDs.