I do see your point though, for all intents and purposes, for normal every day usage there really is no discernible difference between pseudo and true random number generators.
However, the decay of an atom, technically, is superior, as it is completely unpredictable.
Pseudo-random number generators use an algorithm with values pumped into the algorithm. If you know the algorithm, and the values, you can predict the number that will be generated.
As an aside, the decay of an atom is almost always used in randomness tests of supernatural claims, as it is thought by some that the mind can affect the decaying process.
"All of our behavior can be traced to biological events about which we have no conscious knowledge: this has always suggested that free will is an illusion."
- Sam Harris