I genuinely don't know if there's any reasons beyond laziness & not caring to not use vegan milk? There's so many kinds of vegan milk that are better in every way to non vegan milk.

Allergies/issues? Unlike usually with vegan stuff, vegan milk is far more accessible to this than actually non vegan stuff. As far as i'm aware, vegan milk contains milk types that are better to any kind of barrier to it that you may have. Can't have much potassium? Rice milk etc

Taste? A lot of vegan milks like coconut milk are literally well known for being better tasting. It's more like, too lazy to try out vegan milks to find out which has a better taste.

Cost? Vegan milk costs about the same from what i've seen?

I will add a disclaimer: this is based on Australia, if these aspects are different anywhere else in the world, I extremely apologise, I don't claim to be heavily fluenced on the topic. This thread is a discussion/question, if anything, because I don't understand.

turns out vegan milk is apparently twice as expensive in America, proof that capitalism is bad, they're the same price at my local grocery store.

This wasn't about "going full vegan" but just, the matter of using vegan milk.

A lot of places don't stock more than a few types of vegan milk. Also good to know! Thankyou