Using After Effects for animations really makes a difference but this is not what Lumion is about I think.
You could spent easily spent 50% of your 3D budget again for post editing your footage with greenscreen stuff and such.
Just imagine using a green screen (green flat surface placeholder) in Lumion for an advertising billboard. In After Effects you can replace this easily with an animated billboard recorded somehwere else. In you final movie you will have an animated billboard then. Its no rocket science.
You can do some nice post straight in Lumion with the on-board effects. This will be good to go for 90% of architects or clients. If you need the extra portion of visuals and eye-candy then go for post editing and spice up your animation like it the movies you posted.