The command is used for exactly what you saw! If you want the static route to only resolve over a certain physical interface then you'd configure it this way.
This is very useful when you are redistributing statics and only want this router to inject the route when it's directly attached interface is up.
If you do not have this and it still has a route to 10.0.0.3 via another router the static route will remain in the table. You may then end up with inefficient routing