It's a lot quick getting to choose from available reactions instead of taking a whole micro turn.
Pop ups may seem annoying, but they're not that different from quick-time-events. A window can be a bit drab, so an action icon that prompts the player to press "R" to use the reaction and "Space" to cancel would be preferred. Or some other simple scheme.
It can have the visual appeal of God of War with the functionality of Solasta.
