Similarly drag a folder into a Save dialog and it will switch to that folder.
Drag a file onto the "Open..." button on a web page to skip the open dialog entirely.
Drag a file into Terminal to paste that full path into the terminal...
And the far decried HFS+ file system had a feature I hope they will maintain in APFS. When you moved or renamed a file around, most of the time even third party app managed to figure out the new location of the file when seeking for it instead of just displaying a broken path dialog.
And this replacement only occurred if the resource was not present at the search path. Meaning that moving and replacing by a similarly named file result in similar file being used, while moving result in suggesting new location.
Don't know what's the behavior is as of today, and maybe by now Linux also provide this reliably, but first time I've seen this was even pre OSX I believe. And maybe there is a simple trick, but it looked like black magic for the 20 years me.
That was the case (and created a huge debate) back in the old Carbon vs Cocoa days
Infamous tech note 2034: https://mjtsai.com/blog/2014/10/08/the-source-of-technote-20...
Get to the Open dialog, activate App A, click-hold on the little file icon next to the file name on the top bar of App A and drag it onto the Open dialog over at B. Suddenly, the dialog has the appropriate file selected, wherever it happens to reside on your file system. Magic!
Edit: literally everyone beat me to it.
You mentioned this twice, and now I'm intrigued. What exactly do you mean by this?