The vanilla is going to interact with hundreds of volatile compounds during cooking while going through chemical changes. These things change the overall flavor. There's so many different things that can change how the end flavor comes through. Time and time again, it's been shown that the real vs fake vanilla thing doesn't matter for more complex foods (read: baked goods where maillard reactions are going to be common and the volatile aromatics present in real vanilla get destroyed)
In ice cream, cocktails, whipped egg whites, and other foods that are minimally processed, the complexity of real vanilla makes a big difference. I'll eventually make some batches of cookies and small cakes and compare.
The vanilla is going to interact with hundreds of volatile compounds during cooking while going through chemical changes. These things change the overall flavor. There's so many different things that can change how the end flavor comes through. Time and time again, it's been shown that the real vs fake vanilla thing doesn't matter for more complex foods (read: baked goods where maillard reactions are going to be common and the volatile aromatics present in real vanilla get destroyed)
{1}https://www.epicurious.com/expert-advice/real-vanilla-extrac... {2}https://www.cooksillustrated.com/taste_tests/455-vanilla-ext...
From- a reformed professional chef.