What a wager-free welcome means in practice
Most welcome offers lock your deposit and bonus together until you've bet a multiple of them. A zero-wager bonus works differently: the bonus is added, and whatever you win with it can be withdrawn without playthrough. Suppose you deposit A$50 and receive a matching bonus of A$50 with no wagering. If you finish the session with A$140, that A$140 is withdrawable, subject to the usual checks and limits.
Compare that with a typical 40x offer, where the same A$50 bonus would need A$2,000 of bets before anything could leave the account. That's why a wager-free welcome can be worth more than a free spins offer with heavy wagering. It still needs your own deposit, though, so it isn't a no deposit bonus in the strict sense, and the Goldwin bonus you claim at sign-up is the 25 spins.
Before depositing, open the bonus terms and look for three things: confirmation that wagering really is zero, any cap on winnings from the bonus, and whether the 250 free spins carry their own wagering. If those match the headline, the welcome package is unusually simple to cash out.