*an attacker will surely notice...*

Again, you are presuming a cryptographic application. No such presumption is warranted based on the root node.

*Moreover, in terms of randomness, a random shuffle and just choosing a random number are vastly different.*

What part of "indeed, a random shuffle of a known interval isn't the same thing as a set of random numbers... I never said they were the same thing." was unclear?

*... the other is chosing a member from an ***infinite** set with replacement. (emphasis mine)

A random number need not necessarily be chosen from an infinite set. Furthermore, an infinite number of randomly chosen numbers from a finite set is equivalent to a random selection from a continuous interval (infinite set). Therefore, a random shuffle (or multiple random shuffles, depending on the desired cardinality) can be transformed algorithmically into a random number suitable for cryptographic use.

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