In table Q&A tasks people are using stuff like BERT to represent a table (where data can be non-sequential, aka you can rearrange table columns and still have the same info).

They do that to represent a structured table as an unstructured text and perform question answering over it using the table as the context. But to be frank, it is not fully non-sequential data representation as the user's question in the end is a text, which is a sequential data source.