IIRC the framework it‘s built on is so ancient it didn‘t allow for that, they needed to re-write the whole thing to „fix“ it, and this is what they came up with for that. DF‘s Alex said as much in one of their podcast episodes. All just paraphrased by me of course.
I don‘t think the performance hit is by design or intentional anyway, so hopefully the current screw-up is gonna be a nothing burger by the time the app‘s mandatory (if it ever will be).
Turning off invasions while still playing coop you mean? Cause offline mode turns off invasions (duh). I guess invasions are part of the thrill in their mind and after a random coop sunbro and I were invaded by a phantom while super low health and outta potions way into a dungeon in Dark Souls and managed to survive by hiding away together with no voicecomms, it‘s hard for me to disagree with them lol