THE primary reason to write unit tests is to help you design the functionality. So “going back to why you should write tests in the first place,” you actually can’t replace your unit tests with integration tests. And, since you don’t write any code (or at least code without tests would be an extremely rare thing), you would not have a situation where all or most of your tests are trivial.

The type of unit test you describe is often just testing that your framework does what it does (and it should already have tests). But really you should be concentrating on testing your business logic.

It’s fun and gets people to click to say you know better than best practices, but best practices are there for a reason — and work best when you actually understand them and do them right.