On centralized platforms, because there is more regulation and a smaller percentage of various overvalued scams. On decentralized platforms, it is easier to promote various dubious projects, which were originally conceived as just making money on the audience. There you can launch a project anonymously, there is minimum control by services and more opportunities for various exploits, as decentralized platforms are based on the interaction with smart contracts. In addition, centralized platforms have better liquidity and audience.