The company I work at uses KMP in order to develop web applications and backend services with a shared code base. We use the technology in production and have had great success doing so. In my opinion the biggest benefit apart from Kotlin's type safety is the ability to write shared data models and validation logic in a single code base shared between our different targets.
I do, to some degree, agree with the point that people tend to refuse adoption of new technologies and can observe this behavior at work as well. However: In my company, those people mostly turned out to be shitty developers anyway, generally unwilling to learn new technologies and tech stacks and without any actual arguments against the migration. They are a minority though and didn't manage to convince people otherwise.