Gambling with bonus is a great way to try out a new gambling platform, most of the sites where I have signed up, did have some kind of free bonus to kickstart my gambling.
Faucet, i think is a strategy by online casinos to let their customers feel/try their games for free thus enticing them to bet with bettor's own money if they are already comfortable with the site.
@XinXan
My question is, sites offering free bitcoins, are they legit?
The quantity of free bitcoins offered by the gambling sites are not much worth of money. You cannot become rich if you keep on collecting those faucets from gambling sites. These faucets are only for people to try and test the site before actually they can deposit and play with thier own bitcoins.