Freebitco.in has enormous brand awareness compared to other faucets so altcoin versions of it could be reasonably popular. Especially if the altcoin is a fairly popular one like Litecoin. According to
this thread, almost 1/3rd of altcoin owners don't own any bitcoins at all. The number is also probably even higher for certain altcoins like Nxt which aim to supplant BTC.
I get many requests to make altcoin faucets but the dogecoin faucet that we have has been operating at a loss for a while. Click through rates for ads on it are half of the bitcoin faucet, people don't gamble much and most withdraw immediately after each free roll. The loss isn't too much though so I plan to keep it running for as long as I can, but I have stopped actively promoting it and it has put me off from making any more altcoin faucets.