So...I tried making some oat milk yesterday. Here's what I found:
It's very easy to make.
Super cheap to make.
Left it in the fridge for several hours and it didn't separate.
It tastes good, but it left a chalky mouth-feel.
It's good cold, but when I heated it up, it coagulated and got lumpy, probably because of the starch content.
Since I usually use most of my plant milk heated up and added to my coffee, I don't think that oat milk wouldn't work for me. However, cold, maybe with some sweetener, vanilla and cocoa, it might make for a nice chocolate shake.
That's my humble opinion on that.