There is a huge difference between having an ACID store of Truth surrounded by eventual consistency, vs making even your store of Truth eventually consistent. You're basically doubling or tripling your work for any given constraint because you have to both monitor after-the-fact violations and build in a way to resolve those violations.
This is on top of regular "nope, can't do that" code that you would write in both systems.
It's just the opposite, in my experience. If you have an ACID database that's supposed to represent the current state of the world, you have to handle both transaction rollbacks and logical inconsistencies. If you have a streaming system where you record an event log and generate the current state of the world from that, you already have the logic to recover from inconsistencies and can reuse it.
This is on top of regular "nope, can't do that" code that you would write in both systems.