Are you ”new customer offers” on betting sites legit?

Not much of a gambler. I absolutely hate losing money so only place a bet once every 6 months or so when I fancy it. But some of these new customer bets look quite appealing. Just saw one from paddy power which is what prompted this post. They’re offering 30/1 odds that a goal will be scored by either team in an upcoming fixture between Liverpool and Chelsea. This seems like a no brainer, to the point where I’m thinking it must be too good to be true. Is there usually some kind of catch to such new customer bets?