Soloing everything was not an edge case in 0.6x-0.7x. It was optimal and relatively easy but tedious to do. Even today, I try to solo some fights if I can get away with it to conserve resources. It does not have to be big detachments, but smaller patrols or equivalent. Not quite big enough to justify deploying your fleet (because you lose more money than you gain), but big enough for a single ship or few to struggle without cheese due to AI's favorite behavior. A small squad will probably take casualties, but a well-piloted flagship can try to solo the (small enemy) fleet.
Because of the AI's behavior, the enemy will disappear while you wait in the corner, and you can sit there as long as you need to recharge or regenerate everything without peak performance ticking down. Not applicable in fleet action, but very useful for solo action.
Also, it could be for one-on-one fights, like say... your small flagship against a small Remnant frigate. You made a mistake, and took too much damage and only have a sliver of hull left away from death. Just run away to the corner and have hull regenerate, then try again.
Simulator is still good for testing because it remains mostly applicable to real campaign fights.
Now, hull regeneration would be very handy in battlestation fights if I have it because the battlestation cannot move... or a royal pain if the battlestation modules have it too.
Do not forget that current half in-combat repairs help keep you in the fight, and when stacked with Damage Control 2, the ship is nearly immune to knockout due to repair times being so fast.