As with every free service, concessions must be given (most if not all internet services have Terms of Service that might be considered as abusive). We decide if the advantages outweight the inconvenients. In my case, for Discord, it does - but YMMV.

And then, it is always possible to configure and limit the amount (and veracity) of the private information you provide. And there are additional privacy tools that can be used (uBlock, AdBlock, NoScript, Mozilla's Firefox come to mind). As in all things internet, maximum security can be optimized by staying offline and remaining under constant parental supervision, but below that extreme, reasonable concessions (both for the user and the service provider) can be made.