If TripleByte's onsite interview allowed me to skip the onsite at the hiring company, then I'd be all for it, but it is like it's just a layer of friction.
For the record, I've had zero problems applying to companies by either emailing them or getting contacted by them via LinkedIn, email, etc. I just don't understand what benefit they bring at this moment. Maybe if the job market tightens and they were exclusive providers for companies, then sure, but all the SV companies have teams of recruiters emailing people all day long. As a hiring candidate there's no reason why I would want to go through their onsite.