In HH there are 3 keys - one to lender, one to borrower and one to HH. You need to have 2 keys at least to move collateral.
In Debifi 4 keys - lender, borrower, Debifi, authorized (independent) key holder. You need to have at least 3 keys to move collateral.
If there is dispute - support aģents will solve it and co-sign with the winning party. But tbh it's rarely the case. Game theory and consensus are powerful tools 😎
I still trust code more that a third party. Any of these platforms could act against me for any number of reasons.
From being in cahoots with the other party to simply steal my shit, all the way to being forced to give up the key by a criminal actor, like a government agency. Also, human arbitrators make subjective interpretations and I may still disagree with their opinion, and there's nothing I can do if they decide against me.
The output of a smart contract is neither interpretable nor capable of conspiring or of being pressured into acting in a bad way.
In the case of Debifi, there are several parties involved + the key generation/distribution code is open source. Code can be always modified, so the best approach is code + trusted (legit) party.