While there might be some benefit, most of them are snakeoil. Effectively they're just sending polite emails to "people search" websites to remove you from search results. The real, very harmful, data brokers are background check systems (LexisNexis), credit bureaus (Equifax), and insurance industry registries, which there is effectively no way to opt-out short of faking your death.

Harm depends on your threat model. For a streamer wanting to avoid being swatted then the typical data broker removal service could be quite helpful. I agree a big part of the problem is lack of understanding that the removal services only work at one layer.

There's probably even more than these, but here are some from the video: Healthcare data brokers, fraud data brokers, financial data brokers, marketing data brokers, people search data brokers.

Good video explaining the situation with data brokers and the removal services: https://www.youtube.com/watch?v=iX3JT6q3AxA