Not sure China actually needs to invade Taiwan - it just needs to be patient. cf Hong Kong.

Totally agree with you about the dangers of autonomous killing machines - I think the two key problems here are.

1. Reduces the political cost of going to war. Though as Iran has shown, there are other ways to exert political pressure even if the other military can hit you with almost impunity.

2. This is really a follow on from the first - low cost ( in all meanings of the word ) weapons makes asymmetric warfare available to all - and this won't be limited to governments.

On the positive side one of the potential outcomes of 2. is that countries and the world will need to operate on the principle of consent, as force will be nigh on impossible.