> To me, this article misses the mark.

Yes, I agree. The blogger shows a fundamental misunderstanding of what it means to "make invalid states unrepresentable". I'll add that the state machine example is also pretty awful. The blogger lists examples of usecases that the hypothetical implementation does not support, and the rationale to not implement it was that "this can dramatically complicate the design". Which is baffling as the scenario was based on complicating the design with "edge cases", but it's even more baffling when the blogger has an epiphany of "you need to remain flexible enough to allow some arbitrary transitions". As if the whole point was not to allow some transitions and reject all other that would be invalid.

The foreign key example takes the cake, though. Allowing non-normalized data to be stored in databases has absolutely no relation with the domain model.

I stopped reading after that point. The blog post is a waste of bandwidth.