Earlier quoted context omitted.
We use pea milk with our kids because they're lactose intolerant. Pediatrician recommended as long as they're getting more protein and fat elsewhere in their diet (which they do). It doesn't hurt that peas don't care how they're raised and treated to produce milk. Dairy milk is not nutritionally necessary in any age cohort. If you enjoy it, that's fine of course, but it isn't required if you don't.
I just think you're damaging your kids by not giving them milk, which is the most nutritious thing you can feed a kid. Also, your kids may be lactose intolerant due to other stuff in their diet, like gluten or other toxins in plant-based foods that lead to a leaky gut.
Also, there's a fairly foolproof test for lactose intolerance.