These mints will be operated by users who already take the risk of running or using darknet markets. As mentioned in the post, users of custodial darknet markets assume the market could shutdown one day and funds won’t be recoverable.
All DNM users, vendors etc. are anonymous but everything works based on some reputation, due diligence and calculated risks.
Mint operators at present have the same risk of getting shutdown if one of them becomes too big. Doxxed operators and clearnet used for them makes it easier to target. Custodying funds and providing anonymity is illegal in most of the countries irrespective of use case.
This post just tries to find the right use case for eCash mints in which users have the same threat model.