Someone already answered, but a deeper answer is: alcohol does change the way flavors are expressed. Some substances are water soluble. Some are fat soluble. Alcohol does a pretty good job of breaking down some substances that don't break down in water -- but maybe aren't fat soluble (but they could also be). You may notice that many/most degreasing products in your kitchen contain a non-potable form of alcohol -- for this very reason.

So, if you introduce alcohol into food, the alcohol can react with the other ingredients, and introduce subtle changes to the flavor -- because of what I described above. There may be a chance that it can also help as an emulsifier (i.e. helps to blend oil/fat and water) to better combine the cream and tomato.

Additionally, if the booze you use has its own flavor profile (like wine, or bourbon), you'll be adding those flavors as well. Risotto absolutely needs white wine (or verjus) or it tastes "flat". Same with beef bourguignon.

Vodka is a neutral spirit (for the most part), so the flavor profile will be secondary to any other property its inclusion brings.