3...Nxe4 is not "a mistake"- while not as good as 3...d6, it's entirely playable.
3...Nxe4 4.Nxf7? Qe7 is a genuine mistake.
How is that playable for black? Where is the compensation for that pawn?
I would play this line in tournaments, if you say that it is playable then it must be, but I don't see the compensation for that pawn.
It would be a big surprise for everyone :D
This is one of my favorite openings, and THIS
is a famous trap I have used, even several times on SAME opponent! If my opponent refutes it, I play the Ponziani instead.
What if you rearranged the back rank and played fischerrandom? Would that pattern work?