No you are wrong, faucet is not a must so any sites is free whether to provide faucet or not. Look at what have just happened at Primedice and Stake, they have just removed the faucet so it means that not all gambling platform provide faucet. Faucet is also not a thing to test gambler's luck, but it is to test the game only. I will prefer to see one time bonus for a new site like this if the purpose is just to test the game before depositing.
faucets are great tools to attract players , a new site without a faucet lowers the audience significantly
it is due to the fact that the site is new and not trusted just yet
thus an average gambler will be cautious to just deposit some amount of coins to test it , besides they usually have minimal withdrawal limit
so this forces you to deposit at least 10$ ( usually more ) if you are planning to withdraw later
it is up to admin to decide if the faucet is a must or not , if they can provide proper security and detect abusers and bots then why not?
but a new site can be easily abused by bots and faucet hunters , simply because there are many people with unlimited time who can create hundreds of accounts to try and reach the withdrawal from nothing , in this case this could become a burden very fast