You can have scenarios where you would need to add files as attachments to the Email. The attachment can be required from the sheets while adding to the Emails task being triggered from the application. In such scenarios, you would use the LOOKUP formula to fetch the attachment from the sheet and also use the FLATTEN formula to convert Array of Arrays returned in LOOKUP formula to a single array.
The formula would be built as follows:
- file_col is a FileUpload Column Type