It is not ridiculous to sacrifice a knight on f7 for an advantage in development and a quick attack on the king. This happens in, for example, many lines of the King's Gambit.
In this case, you sacrifice a knight but you get a pawn. So you are only losing 2 points. And you also make it difficult for the black king to get safe. The question is, would the advantage of having the black king being exposed equal or greater to the 2 points deficit you have?
I think not. I would much prefer black in this position (I am talking about the first position where white sacrifices the knight).
My reason is that if you get a developmental advantage (in exchange for loss of material) you have to take advantage of it quickly. If you do not then your opponent will unravel their pieces and reach a similar level of development; eventually you will just be left with a material deficit for nothing. In this case there is no easy way for white to attack the king. White has no pieces out. The black knight on f6 is strong. The h5-e8 diagonal is hard to attack. The black pawn on d5 is a good one. The bishop on c8 is ready to come out. But by contrast, white has nothing. So I am not even sure that in this position white has any developmental advantage (if anything, black is more developed because all white's moves have been with a piece that is now gone). So I just do not believe that white has anywhere close to sufficient compensation for the loss of material. I think it is a poor opening for white.
#2 Black
So what do you think about the fast sacrifice knight strategy?
Playable or not?