Kotlin dataframe is certainly not as feature-rich as other much more mature offerings. However it leaps over some older libraries in usability, primarily by leveraging Kotlin's core features -- typed variables, non-nullability, simple data classes with embedded functions, speed from compilation.
This video is a presentation I gave at the November 2022 San Diego Kotlin User Group, introducing dataframe, comparing it to other language libraries, but also to SQL and to native Kotlin collections like lists and maps.
I am very proud to announce that I've been selected to give a similar (a bit shorter) presentation at KotlinConf 2023, the world's largest Kotlin language conference, in April 2023. Very excited, hope to see you there!