"A key requirement to determining if there is an armed conflict taking place would be the deliberate intervention of members of a state’s armed forces."
This is from a reply to a parliamentary question (and other parts of the reply may be of interest as well), and a likely unintentional admission of very far-reaching consequences:
Offensive "cyber" ('hacking') activities would rather be considered an act of war (armed conflict) if done by a (para-)military bureaucracy than by a civilian bureaucracy or mercenaries.
There are many reasons why armed bureaucracies trying to develop a 'cyber' arm look a lot like a typical bureaucracy trying to grow in power and size, but this one is in my opinion a knock-out to the idea of offensive 'cyber' capabilities in armed service.
You would simply get away with offensive actions more likely if you are known to not have such a (para-)military cyber arm. The armed services are systemically disadvantaged in this regard.
Let's assume our government or alliance definitely doesn't like how some other country of significance is run by a tyrant, and we want to tip the scales towards an ousting as for example against Ceaușescu in Romania. A great or superpower backs this tyrant, though - and we don't want a much more intensified conflict with them. Maybe we could disrupt the censorship, reshuffle banks' funds towards dissenters, dig into bureaucracy files and expose/publish appalling corruption, maybe we would even want to distribute a call to every adult to go on strike the next day, or rise up.
All of this would create much more backlash if the entire world knew that we had this capability in the armed services than if instead we merely employed mercenaries - many of which would probably not even live in our country or not even be fellow citizens.
This isn't even about the technical ability to trace malicious activity to a source; we know that eventually the usual suspects would be blamed quickly (see Stuxnet), but evidently it makes a great difference whether this source is a (para-)military bureaucracy or not.
This also means we would likely get less often falsely accused if we have no institutional, (para-)military ability for such offensive actions.