Given the could convict him right now, my guess is that they are trying to bargain in some way to get access to the HDDs as a way to 1) try to find the children being abused and 2) access a wider ring of child absusers etc.
Given the legal grey area this all appears to be in and the potential upside of getting in to the HDDs this seems like something the authorities would be ok doing while the law catches up.
Or they're using it as the case to challenge encryption. If this goes to the supreme court, a decision on this will set some major prescient on encryption.
Given the legal grey area this all appears to be in and the potential upside of getting in to the HDDs this seems like something the authorities would be ok doing while the law catches up.