[kgwgk]

> How could you use the two "variables" in the same expression?

Do you expect to be able to use every random variable which can be conceived in the same expression?

If you object to the name “conditional random variable” [+] that’s debatable, but if you say that the resulting thing is not a random variable I think you are wrong.

Another thing that is a random variable, even though I suspect you may not like it, is the probability distribution of a random variable.

[+] which I don’t think was actually used by the OP, by the way.