One of the attractions of this variation probably lies in the fact that White resorts to "forbidden means" (a developed piece is moved again). Although this is not a violation of the rules of the game, it is still a provocation. If White wants to get away with it, they need to do some work in the run-up to the game. If Black has done their homework and knows the variation, there is usually an exciting and intense competition for the better ideas.
This variation often leads to unbalanced positions. An understanding of chess and the ability to correctly assess the circumstances in individual cases play a key role.
If you want to play this variation as White, you should familiarise yourself with the essential ideas and variations beforehand. Otherwise, you run the risk of quickly finding yourself at a disadvantage against an opponent who knows the most important defence ideas.
If you allow 4. Ng5 as Black, you should have a concrete defence idea.
This variation is a challenge. White should only play the knight loss if they know what they are doing. Black needs a basic knowledge of the variation in order to be able to develop it as their playing strength increases. A solid foundation of chess knowledge and understanding makes it easier to learn this variation. If this is the case, this variation is an excellent way to improve your understanding of chess. In short, a comprehensive training ground for advanced players.
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