I'm aware there is a mega-thread about this, but just want to add.
The current method of setting a toggle as to whether or not the computer automatically uses the reaction or not is not great.
I've heard you don't want to "interrupt the action" or something, but seriously... this is a major benefit of going turn-based. If you want the action prompt to be stylish and maybe give the action a slow-mo matrix feel and give the player a time-limit to choose yes or no, that's fine. Heck, applying a time limit for decision is common in tabletop.
But just setting Reaction to use or not use removes LOTS of functionality in how they were designed.
It's going to be a point of frustration when, say, a Counterspell goes off against a cantrip and is not available to stop a major AoE.
