I just want to throw out that there's nothing about this that won't work for !("high scale, complex") sites. I worked at a ~20 person startup and we arrived at the same decision regarding database migrations and, you know what, it wasn't that hard and it didn't take that much time and it made deploys a lot smoother.

I see a lot of other people mentioning the annoyance factor. Like anything else, you get used to it, and appreciate its advantages.