I'm trying to play devil's advocate on this, to work out the logic.
This man can afford a good lawyer. And as such will come up with a good defence. These are also exceptionally vulnerable women involved. And he's an exceptionally manipulative man.
So put him on trial and even with videos he's going to pledge not guilty. And probably claim that these women consented and were into weird shit or were exploiting him for some reason (money, visa, drugs). And he'd put them on the stand for it. And have they endure an appalling cross examination.
Which may not be in the best interests of those women and may mean he gets off completely through a loophole or just gets a conviction which is small and he's out again pretty soon to repeat the cycle. Because the sentences available for his crimes are wholly inadequate. (We've seen too many cases where child porn convictions are not custodial or rapists getting remarkably short times behind bars).
So they've made a judgement call in refusing him to get a kick out of that, and to have access to his victims at trial (remember men who use coercive control, like to use authority and the system to continue to harass and control their victims - the process is punishment).
Going down the civil route is interesting because if he violates that, they then can bring other charges without involvement of victims in the same way. And it puts a ring around certain behaviours and makes it much more difficult for him to argue some ridiculous loophole. Or for him to be a flight risk so he can go abroad beyond the jurisdiction of the court and do similar abroad.
I don't know. They've clearly made a tactical decision on this for a reason. It's easy to go down the conspiracy route of what does he know and who does he know. That could well be true - but I also think before getting to that there's possibly other considerations too.
Central in my mind is it justice for the victims to be dragged through a distressing and possibly public trial and being cross examined by this piece of shit only for him to be out again in a couple of years free to do it all over again?
It feels like an admission that the sanctions available through the criminal courts are wholly inadequate for a repeat offender like this and that actually the law needs looking at by politicians to resolve that as it's beyond the scope of the police and court.