I think it is best to approach any new food as being an entity unto itself and not even allow yourself to think that maybe it tastes like
XYZ. That way you do not build up expectations that can easily be dashed....And your kids won't feel like you tried to dupe them if you say it is supposed to taste like milk, but they judge it otherwise.
Along the same lines as comparing soy drink to milk , is referring to tofu as "soy cheese," "like cheese," or even "meat substitute". Tofu is not any of those things. It is a food of long standing use and history and not just invented to allow someone to begrudgingly avoid meat or dairy products. Does soy drink have such a history? I don't even know.
Hope you find it versatile and tasty. If you like it sweetened and flavored, I have no doubt you'll experiment with stirring in your own sweetener and flavors.