Unit tests are just as important as integration tests as long as they're tightly scoped to business logic and aren't written just to improve coverage. Anything can be done badly, especially if it is quantified and used as a metric of success (Goodhart's law applies).
Integration tests can be just as bad in this regard. They can be flakey and take hours, give you a false sense of security and not even address the complexity of the business domain.
I've seen people argue against unit tests because they force you to decompose your system into discrete pieces. I hope that's not the core concern here becuase a well decomposed system is easier to maintain and extend as well as write unit tests for.
Integration tests can be just as bad in this regard. They can be flakey and take hours, give you a false sense of security and not even address the complexity of the business domain.
I've seen people argue against unit tests because they force you to decompose your system into discrete pieces. I hope that's not the core concern here becuase a well decomposed system is easier to maintain and extend as well as write unit tests for.