4...Nc6 is more historic with respect to this famous mate. At which point, White should not sac the Knight immediately, but instead play 5.h3 Bh5 and then 6.Nxe5!. Point being that 5.Nxe5? loses to 5...Nxe5 covering the bishop.
Fun to see it live, I'll agree. :)
"Usually in this mate, there's a risk that your opponent will have a knight that can take yours, and if he does, you're down a piece. In this variation, even dxe5, Qxc4, and I am up a pawn."
As Svisky points out if your opponent a Knight on c6 then push the h pawn and if bishop retreats to h5 then Nxe6!
I never thought I would get to use this in a real game, but I did!