Vanilla in Milkshake IPA

[Signoredv]

Hi from Sweden.

I'm brewing my first milkshake ipa. Basically a neipa with lactose. Almost all the recipes I've read contains vanilla.
Is it important to add vanilla to a milkshake ipa? Is it for mouthfeel or for flavor?

 

[thehaze]

Vanilla adds a perceived sweetness and ... vanilla, which, will reinforce the " milkshake " part of the beer.