Kind of funny that "starting you off with all the features that are the same in every product" is a good description of the original motivation for Rails itself. Which is not criticism, the goalposts have moved quite a bit the past few decades.
Rails is arguably “technology batteries included”, whereas this is more like “product batteries included”. There are many Rails sites that wouldn’t use these features, however there aren’t many Rails sites that wouldn’t use ActiveRecord or HTML rendering.
This seems like a great way to put it! At the lower level of abstraction, there's all of the technical stuff, but at the higher level of abstraction, you think more about the product and the business domain concepts.
The thing w/ Bullet Train is that so much work is done for you, that if you don't like an opinion or two that they hold, you really should start from scratch, as tearing things out will just take longer. Its the downside of having so much integration and configuration already done.
Not disagreeing, but wouldn't this be true of Rails itself? It's an opinionated framework. If you like those opinions, it's a great framework to use. If you don't agree with those opinions, you're probably better off using something else.
Having said that, some of Rails opinions are becoming more optional lately.