That was somewhat covered by point b, but yeah, in terms of verification it's tricky to determine if a hardware RNG is actually, you know, random. The other part that makes it tricky is that most hardware RNGs don't produce enough entropy to keep a system fed during active usage so you typically need to use their outputs as inputs to more traditional PRNGs or to periodically re-seed a PRNG which was actually the main thing I was thinking about with point b.