For me, it's more of a question of what's most sustainable. Afaik, soy is planted and harvested in Germany too, but oats are just dime a dozen around here, so I stick to those. Plus, I like the taste a little more compared to soy. Soy yoghurt is vastly superior to oat yoghurt, however. Coconut yoghurt is abysmal except for breakfast yoghurt with fruits and baking 💀