I'm not throwing shade at BG3; I've also enjoyed it, but something about the sheer amount of options and more widely diverging story paths in Wrath just does it more for me. I also like the art style more, but that's strictly subjective and I accept that.
To a lesser and more personal extent, I despise Wizards of the Coast/Hasbro and their recurring attempts to monopolize and bully third party game developers and players alike and I don't like to even indirectly trickle money their way compared to Paizo. Yes yes, no ethical consumption and all that, but Paizo's way less fucked up with both distributing game materials and open licensing agreements.
https://www.polygon.com/23553389/dnd-ogl-paizo-orc-open-rpg-creative-license-announcement
That's all I had to say. If you've already finished BG3 or it wasn't quite to your liking and you'd like an alternative, give Wrath a try. 
I'm not really sure how much replay value I'd personally find in BG3 considering I found some sections to drag so hard and still kind of play out the same way that I don't know if I want to go through them, and where they differ tend to be in contained ways like "you move on to chase after more mind flayer stuff, but now the druids/goblins are dead instead of the goblins/druids."
In Wrath of the Righteous, once the mythic path really takes off, the story can become strikingly different between, say, an angel run, a devil run, a necromancer run, or a Swarm that Walks or a trickster for that matter.
Exactly! I guess you can do an evil run in BG3 if you're okay with losing parts of the game in return for some additional dialogue. The combat system of D&D 5e also doesn't really entice me to try another playthrough as a warlock or something, especially as you can just respec everyone whenever, and let's not even mention the romances. But the mythic paths in WotR really do make an impact on the game, especially mechanically, when it comes to your main character.