Bytedance created all internal tools by themselves. Personally I'd definitely love to join such a company if I'm in that tooling team. Whether they are being used by outsiders is irrelevant because I already bagged the skills.
Eh, I make tooling for a living. It sucks to have nobody using your tools even if they were fun to make. You spend months/years putting something out there that you think will really benefit a company/team/foss and it goes nowhere. It's like painting a painting you love and it getting thrown in an attic.
