I think the benefit of TripleByte is that they will help you find companies where you will perform well based on what they value in candidates, and they will (maybe?) help prep you for those interviews. You arguably don't have the time to interview at 10+ companies, so having them help filter it down to the 3-4 you are most likely to pass interviews with means you potentially have more competing offers with less overall time spent interviewing.

They may also be able to help you find companies you hadn't heard of that would be a good fit for you. Eg if you didn't know company x is hiring type y devs then the relationship could prove beneficial there as well.

That said, I hope they can start offering more value over time. For example, if TripleByte could not only tell you where you will succeed during interviews, but also help you understand how offers are likely to vary that would be valuable. Eg "company A would likely offer someone at your level $130-150k salary and y options, while company B typically offers more generous options, but a salary range of $90-110k". If your min salary is $120k, then this helps you prioritize where you interview based on what is important to you.

EDIT Editing to add that regardless, I don't think you are their target developer. Anyone who can get an interview with these companies is likely going to do just that, while people who cannot for whatever reason (new grad, no flashy names on resume, etc) are more likely to benefit from using a service like TripleByte or Starfighter where if they do well they almost guarantee they get to interview instead of sending out a resume and never hearing back.