The key thing here is that this virtual card is NOT specific. It's generic, depending on whatever card is paired with TR.
How is that key?
Because the pseudo-cantrip framing device with something specific can be completely collapsed into just that specific something. Pseudo-cantrip that draws a pseudo-Militia is effectively just Militia (barring edge cases, yadda yadda).
With TR, the card at the end is not just another TR. Instead, TR+X is re-imagined as X'+X.
If it helps, forget about the entire virtual pseudo-cantrip stuff. Instead, here is a much simpler way of looking at it:
Playing TR+X is a lot like playing X+X.
In this way, it's like TR is becoming another copy of X.
In a sense, "transforming into card X" is like "giving you card X".
In a sense, "drawing you a card X" is like "giving you a card X".
Yes, I know that this is all very loose and abstract, especially after being broken down systematically in an attempt to explain what is supposed to be intuitive. Such is the nature of riddles.