[passer-by-123]

> If all of those extra characters are for extra flexibility (maybe for using more repositories in future?) then it smells of premature optimization. I'll happily do without it.

I wouldn't say it is to use more repositories in the future (I also hate future-proofing code) but rather to make it explicit what is happening on the database side. It aligns well with other ideas in Ecto, such as letting the database do uniqueness checks.

Most of the problematic Rails projects I worked with were because of this coupling between business logic and database that ActiveRecord encourages. But this is nothing new, it is one of the top 3 complaints about Rails.