What value do I bring by buying stocks?

So I've heard it multiple times that investing into stocks is better than buying crypto for example. Since you're actually helping the company. But this doesn't seem to make sense for me. Pre IPO it makes sense, since investments go directly to the company and they can be more productive and create more value. But when I buy some stock using a broker I just give my money to the person that had that stock before me, so the company doesn't really get anything. I don't understand what value I actually bring to the table by buying stocks.