Even if 3.- a6 (because it forces White to place his white-squared bishop worse) or 3.- Nf6 (because it takes many active options out of play for White) is the most successful response to Spanish, Black's alternatives on move 3 should be taken seriously. Because each of the alternatives has its own poison. This is particularly attractive to players who are afraid of the extensive theory of the main variation.
This approach is understandable from a practical point of view. But especially if you have ambitions in chess that go beyond the individual game, such an attitude has its price. This is because it is generally better for chess development to deal with the main variations first and only then play the minor variations.
This fundamental problem becomes particularly clear in the Spanish opening. If you want to play Spanish with White on a permanent basis, you will not be able to avoid dealing with the minor variations presented here. This is also work well invested for White. Because White can decide for themself whether they want to build up rather calmly or emphasise tactically. And in all these variations, White has good prospects of an advantageous position after the opening. After all, there is a reason why these variations are not main variations.
Would you like to learn these openings? You can find specialised opening training courses here:
1.e4 e5 2.Nf3 Nc6 3.Bb5 f5: Search results (chessbase.com)
1.e4 e5 2.Nf3 Nc6 3.Bb5 Nge7: Search results (chessbase.com)
1.e4 e5 2.Nf3 Nc6 3.Bb5 g6: Search results (chessbase.com)