The difference you miss is that the former discourages bad interfaces and the latter does not. There is no "you" in most businesses. There's dozens of people who changes over time. People with deadlines and concerns of their own.

> the former discourages bad interfaces

That does entirely depend on your language and tooling.

> the latter does not

And that does entirely depend on your processes and internal communication.

If your people keep changing, your chances are much less astronomically bad with a monolith.