There is always a catch in deposit bonuses. Typically, it is meant to be hard to to also prevent abuse, and be more sustainable for casinos. Nothing we can do about it unless a powerful authority starts regulating them. That's why make sure to always read the bonus terms.
But not gonna lie, that deposit bonus in your example is not very attractive lol. I doubt many people would join because of it, at the very least I would not lol. And imagine if they placed a high wager requirement for it lol which I hope not.
Most people, especially beginners, don't read casino bonus terms and conditions. As soon as they see a bonus, no matter how small, they rush to claim it, and then problems and complaints begin.
I agree with you that the deposit bonus mentioned here is trivial and not worthy any attention. I'mactually surprised that some people would be attracted to such a bonus! Personally I wouldn'trush to sign up with any site just for a $1 bonus. There are a lot of things more important to research carefully before registering.