This is INSANE!
Sure cuts down on the transportation costs. Imagine if you had to pack them up and ship them out every time you needed them. The waste of time and packing materials alone would be tremendous.
We wouldn't have that problem if we didn't send them out all over the place to do jobs others should do.
I remember reading during the height of the cold war, that having our ASW types stationed on Iceland was akin to having a permanent carrier battle group checking out Soviet Naval activity in/out of those icy northern waters.