Sometimes the use-cases are complex and it is easier to load from an external file the contents of / parts of the body.
It would be useful to have the possibility to load a file in a variable - either in raw mode or base64 encoded.
With Insomnia there was an extension that allowed to dynamically load a file encoded as base64 as the value of one of the JSON attributes of the request body.
It's not the brightest the way the target API was designed, but having the file import trick considerably eased the pain.
For a more generic approach, dynamically loading from external files can be an asset for complex API tests, though ...
Would this feature deserve to be implemented as a native functionality or, at least, through an extension ?