Maybe Coinbase is trying to avoid conflict of interest, Litecoin has proven to be a real coin though it has not sour with Bitcoin the way it used to, but there are still alot of interest and community behind it especially China
So far in my idea regarding about in coinbase it is not a type of exchange sites like as we all know this is more of buying bitcoin only and getting wallet from it. Also not all country affiliated with the coinbase, because my country is not affiliate in the coinbase.