Until you inevitably need a cross cutting concern.

“Oh just this one time”

Then an agent sees the pattern and assumes it’s a best practice. Then your beautiful architecture is ruined.

“Just this once” indeed.

Except that there is typically a feedback loop between the implementation and the module interfaces. While implementing, you discover aspect that makes you adjust, and sometimes completely alter, the interfaces and module boundaries. And that’s not just for an initial implementation, it continues to happen as new requirements come in over the lifetime of the software. Ostensible implementation details continue to inform the architecture.

yeah this is along the lines of what some friends of mine call "core vs. pragmatic modules" or even s/modules/codebase zones/

the idea that if you have a solid core and decoupled modules, you can have "zones" in your codebase where you allow the model to run wild and do a little slop, because you know the blast radius is contained