Can anyone explain to me why the autoplay after 10 ball rule exists? Seems such an arbitrary rule to implement. Also, why is declaration (for tests) considered to be autoplay?

Autoplay is allowing the computer to take control of the game, whereas in test matches when declaring at no point is the computer controlling the game.

The autoplay rule is based on the potential amount of balls a team can be bowled out in, since there are 10 wickets to get, 10 balls made sense. Most categories we're aiming to bowl first since it would take a lot longer to bat first. No ruling has been made as of yet regarding declaring, which is why I rejected the run.

Declaring is something I have considered as including in the ruling for Test match runs, I just haven't had the energy or time recently to sit down and implement it.