Depends on the usage.
Faucet for developers wise is meant for getting free crypto for testing. In Ethereum there is a few test net called Ropsten and Rinkeby, you can claim the token in Ethereum for the testnet in order to deploy contract and test functions. There is no real economical use.
Otherwise, is usually a way to get free cryptocurrency, to encourage more people using that particular cryptocurrency. However, often faucet was coupled with scams. So do be careful when there is a free faucet website.