The difference is that Signal's competitors are designed in such a way that they have to keep this information, and Signal has delayed key features, like user profiles, until they've managed to create designs that don't have these restrictions.
So the logic you're using here is essentially: "since we have to take Signal's word for some part of this, we might as well use services that promise the exact opposite". I don't find that argument persuasive, but you do you.
Not all Signal alternatives store user information on servers. Threema for example has fully decentralized groups and even decentralized profiles (while Signal uses encrypted-but-centralized profiles, and their new Private Groups system moved from decentralized to encrypted-but-centralized as well).
So the logic you're using here is essentially: "since we have to take Signal's word for some part of this, we might as well use services that promise the exact opposite". I don't find that argument persuasive, but you do you.