The aromas and flavors of vanilla extract are exactly what you will taste in your finished product. They don't really transform into anything, the ethanol and water just evaporate and leave you with the dissolved solids from the bean. Tasting it in raw or extract form tells you what it'll taste like in a finished product.
Flour, on the other hand, varies greatly in its end result based on the genetic variant, grade quality, and milling, in combination with amount of water and the mechanical process of mixing. You can determine the effect on the cake by looking at the type and grade of flour, along with its moisture content. I wouldn't advise eating it.
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.
