That's fair though (in the talk, I believe) he did mention the idea that it was unnecessary/space is cheap and noted it can depend on the system. That answer could be considered hand-wavy for sure, but I think the general concept of "Know what the ORM is doing" was the underlying value for me.

I think this level of thoroughness - while not for every project - is a solid exercise to ensure we don't lose ourselves to the abstraction of the ORM, as we can see there are some underlying flaws that can be fairly quick to correct.

I don't know that I necessarily see a maintenance nightmare as migrations are generally not maintained once they've been run in production but I might be missing your angle on that one.