Never use milk in bread. Bread with milk instead of water may be tastier and smoother, but it is much less healthy. In this regard I follow this advice:

“In the making of raised or yeast bread, milk should not be used in the place of water. The use of milk is an additional expense, and it makes the bread much less wholesome. Milk bread does not keep sweet so long after baking as does that made with water, and it ferments more readily in the stomach. {E. G.White. Counsels on Diet and Foods page 316.3}

Milk can be advantageously used in all kinds of unleavened flat cakes.