Beliefs are important, beliefs are what gets us through life somewhat mentally sane.

Beliefs are (for example) the cornerstone of relationships, because you have to believe that your partner really loves you. There is no hard evidence for that so it can never be a fact, only a belief.

I believe that my neighbors don't plan to kill me in my sleep (why should they, I am a nice and easy neighbor), I believe that the person at the fast food corner doesn't spit on my food (and that they had washed hands after using the toilet), I believe that my landlord will some day repair the water damage in my second bathroom (and put all the bathroom stuff like sink, shower and toilet back in).

One could say that belief is behind everything where "trust" is involved. Belief is just accepting something as true, either because it is something that is a concept without hard facts (love, religion, justice, freedom, money, "the good in people") or it is something where the information are lacking either because they are not fully known yet or because it is such a complex topic that having all information is (nearly) impossible.

I believe for example that climate change is real, because I trust (there it is again) the science. I have to believe in this case because I can't have all the information without studying climate sciences, and one can argument that even our best climate scientists doesn't have all the information (models are still incomplete and simulations don't use all possible parameters) so even they have to believe for some parts.

Beliefs become problematic when people take them as hard facts, as dogmas, and become extreme.

I believe that taking extreme positions is always wrong and a way to disaster and suffering. That's one reason why I don't like faith and are against cults of any kinds.

I think it's weird that people even have beliefs. Belief is a dirty word to me.

The more I think about it, the more I realise how less I understand this word.

I believe I'll block op

IMO "I don't know" is a perfectly valid opinion if you just don't know.

Belief is a tool for achieving effects; it is not an end in itself. -Peter J. Carroll

I believe in science. I believe in justice, equality, and freedom. I believe fascism and capitalism is detrimental to humanity.

I do not believe in ghosts. I do not believe in gods, angels or demons. I don't believe in an afterlife. And I don't believe corporations are people.

I do not believe in doors. Does that mean that I think that they should not exist or that I think that they do not exist? Yes actually!

Because as Terry Pratchett astutely notes in the Hogfather belief is what makes the human society possible. We invented justice, mercy, duty, laws, money etc. They exist only because we believe in them. Some beliefs make the world better, other ones worse, and we should try to emphasize the former and minimize the latter.

Read the book Sapiens.

Being able to believe in fiction is what allows humanity to function.

Yeah, of course they do. They literally form the cornerstone of your worldview. If you change someone's beliefs, you change how they see the world. That sounds pretty damn big and important.