Here's one example of the use case I was referring to earlier... my project organizes tests with a directory structure like this:
tests/
test_01/test.py
large_txt_file
small_file
test_02/test.py
some_binary
small.csv
I currently add the "test.py" scripts to my project so that they can participate in searches and exclude the test input files as they don't contain code. However, excluding files from a project essentially "hides" them from view. This is quite inconvenient as the tests refer to the input files and it's often necessary to edit the inputs, confirm that they're actually used by a test, etc.