Quoting Wikipedia: "Several companies have sued the DTCC, without success, over delivery failures in their stocks, alleging culpability for naked short selling. [...] Critics blame DTCC, noting that it is the organization in charge of the system where it happens, alleging that DTCC turns a blind eye to the problem, and complaining that the Securities and Exchange Commission (SEC) has not taken sufficient action against naked shorting"

Doesn't sound that trustless to me. With a decentralized setup as in Quorum at least everybody can calculate how much they have to trust the miners.

If your company has miners of their own, you are part of the whole system and not just using a third party service.