Files can be added to a SharePoint list item. This functionality is called: Attachments
Attachments is by default enabled on lists. When I know that list items will not contain attachments, I disable this setting.
Working with list item attachments cannot be compared to working with files in a SharePoint document library. The later has a much richer experience. For example: A document library allows for editing a file, has version history and Power Automate flows can be run on it. It is also possible to add all kinds of properties (metadata) to a file in a document library.
Working with attachments instead of a document library can be useful though. The best reason for me is that a document library requires a file and a list item does not. When using SharePoint for data storage, I use almost always a list. Using attachments then adds the functionality to add files without adding additional SharePoint objects.
There is no way to add attachments to a list item using the Patch function. It is possible to add attachments with an edit form control. In case you want to use the Patch function and add attachments, you need to combine both technologies.
Power Automate actions related to SharePoint attachments are: