Useful cCiffs

[CHAPtheMACK]

So it seems like from the Friday fun facts that cliffs or going to pretty mutch just be used as a way to block trains until they can be removed. I think it would be cool to have uses for them.
For example:
Instead of detroying cliffs trains can have sloped tracks or there could be tunnels you that trains can go through to stay under your factory.
Have walls bind to cliffs as a natural defense
(Also make it possible to walk across walls)
Have the underground conveyers be used to make conveyers drop a level.