Of course such campaigns are useful, because through them the ICOs obtain several benefits:
a) They can access a broad market of potential investors who, simply for the sake of promoting such ICO, need to be informed about the advantages of investing in that project, which is the first step in convincing them to invest.
b) They promote in an extensive way the brand announced among the thousands of users of the forum who, otherwise, would not have knowledge of that brand.
c) Thousands of dollars are saved in advertising and publicity since developers usually only dedicate a minimum percentage of their tokens to this type of campaign, often less than 1%, when a massive campaign can often cost 40 times more.