Using data frame analytics requires source data to be structured as a two dimensional "tabular" data structure, in other words a data frame. Transforms enable you to create data frames which can be used as the source for data frame analytics.
This functionality is experimental and may be changed or removed completely in a future release. Elastic will take a best effort approach to fix any issues, but experimental features are not subject to the support SLA of official GA features.
Data frame analytics enable you to perform different analyses of your data and annotate it with the results.