The only issue is you can't do a clean switch statement that matches on the specific value of a field, but nested switch statements aren't that messy.
The trouble with this approach is that there's a lot of mental overhead in dotting all of your i's and crossing all of your t's. It's draining, so you start to, e.g., shoehorn additional functionality into existing classes instead of making new ones.
You eventually wind up perceiving the abstraction as costly which lessons your use of it at the expense of producing a more elegant solution to the problem(s) you're solving.
tl,dr? The ability to just state "Darmok and Jalad at Tanagra" is transformative when the alternative is telling an entire story every time you want to reference a complex idea.
The modelling aspects can be simulated, yes, but that's barely half of the benefits of ADTs. Pattern matching is a big ergonomic benefit.
The critical thing is that the compiler (or macro system) needs to check that you've checked all the alternatives.