Litecoin is a backup for bitcoin, as i view it.
If bitcon gets fucked by this blocksize debate, the most likely litecoin will take its place.
All merchants can easily integrate litecoin just like bitcoin, so the transition would be very fast.
that is pretty much it. with the second biggest blockchain and a solid community it has its place.
It is like Silver to Bitcoins gold

(price goes up and down all the time. if bitcoin is succesful, Litecoin will be too)