I've never quite understood what the lenses are supposed to be for. Are they actually for doing the opposite of fake miniatures? -- i.e. increasing depth of field.
Tilt changes the plane of the depth of field so that objects at different distances are in focus at the same time, shift changes the plane through the centres of the lenses, whilst keeping them parallel.
When (plate | rollfilm) cameras had bellows, you could sometimes shift the objective lens with respect to the film plane, usually to adjust a wide-angle shot (say, a building) so that the verticals remained straight. 35mm SLRs lacked that capability, and building shots on wideangle lenses invariably ended up with converging verticals due to the camera not being parallel to the building sides. Eventually someone thought to make a lens that allowed you to achieve similar shots to the bellows cameras.
I've never owned one, but I did once run a rollfilm through an old
Coronet bellows camera, and the effects whilst not the same, are somewhat similar - the lens is of relatively poor quality, and the aberrations mean that the focus falls off towards the edges anyway. Unfortunately, I haven't got those pictures in digital format (have you seen the price of Medium Format scanners?
)