Solasta reactions are horrible. Pop-ups are clunky and will become very tedious to deal with if you have a bard in a party. Just because DnD purists want a videogame simulator of the rules they obsess over doesn't mean that the majority of casual players will like it.
I agree, 100%. I have zero interest in popups throughout the game. I shudder even thinking about it.
As for DnD purists, of course they exist.
The popups really aren't that bad in Solasta. Like I said, paladin smite popup is annoying because it's every time you hit, which is almost every attack, and when the paladin gets 2 attacks... Ugh.
But things like Counter spell work pretty well. Enemy is casting a Fireball. Popup. Do you want to use Counter spell? Click Yes. Shows you cast a spell to counter enemy spell. Doesn't happen that often and it's super quick. Same with Shield.
And some Reactions are simpler and could be handled via Scripted Reactions. What I mean is how Larian kinda has AOO enabled currently. If enabled, and an enemy meets trigger requirements, the Reaction triggers. This could easily be done with Shield. When you enable Shield spell as a Reaction, you get to pick "Any Attack" or "Magic Missile Only" or both. Now, no popup for that.
Smite, which isn't a reaction, could be handled mostly like how BG3 has implemented the Battlemaster combat maneuvers. The only time a pop-up would then appear is when the paladin does an AOO. Then it would ask if they want to use Smite when hitting as an AOO. Again, wouldn't be too often.