I think they make the biggest difference when testing data pipelines (which have historically been difficult to test). You can now easily test out compatibility

I think they make the biggest difference when testing data pipelines (which have historically been difficult to test). You can now easily test out compatibility between different versions of databases, verify data types, embed as part of your build, etc. I believe the next step, once using test containers, would be automating data generation and validation. Then you will have an automated pipeline of integration tests that are independent, fast and reliable.