“Use Selection for Find” is a standard capability across most macOS apps and especially IDEs and text editors (via Edit → Find or Command+E).
It’s efficient if you’re doing a lot of finding and copy/pasting, as it frees up your clipboard for the latter.
This is useful specifically when using ChatGPT as a coding assistant, where the instructions that come back from ChatGPT are often (essentially) “find this snippet of code in your code base, and replace it with this new snippet”.
If ChatGPT for macOS supported Command+E it would save a lot of switching back and forth between ChatGPT + IDE. In other words:
Command+C, Command+Tab, Command+F, Command+V, Command+Tab, Command+C, Command+Tab, Command+V
becomes…
Command+E , Command+C, Command+Tab, Command+G, Command+V
Two fewer app/context switches and three fewer steps 