Sorry but…
It is the same type of marketing as we can see in stores where new food brand can offer us to taste their product, you are not losing anything there while discovering new opportunity. In terms of broker some traders manage to “unlock” bonuses for withdrawals, they don’t tout that on forums just making money slowly and quietly. It doesn’t mean that bonuses are absolutely safe for newbie traders, but taking for example Hanseatic broker mentioned above, its 20 lots to trade with bonus to be allowed to withdraw all you’ve earned. It is possible but agree extremely difficult maybe 1 from 1000 registered will be able to complete that.
I reiterate what you are losing here if you are not gambler?