My general expectation is that dragging and dropping is a great way to discover an easier way to do something on a Mac, at least if you have a mouse and not a trackpad. I can drag a file into a terminal and get its full path, with escapes as appropriate. I can drag a folder into a “save” dialogue box and the dialogue box will move to that folder. I can drag an application off the Dock and remove it.
My general experience on Windows is that if you try dragging and dropping something, it may perform some kind of action, and it may be consistent about how it performs that action, but it is rarely the action I want to perform. Drag a file into a save dialogue? Obviously, I wanted to move that file into the folder that the save box was browsing!
My general experience on Linux is that drag and drop is utterly broken and will never work so I might as well give up. Even copy and paste is hell on Linux.
I thought dragging a file onto an executable in Windows did open the file with the executable? Dunno about *nix, though if it doesn't work it should be easy enough to implement.