iPhone photos a colleague can actually open
You just came back from a client visit with forty-something photos on your iPhone. You drop them into the shared drive and the project manager pings you five minutes later: "Can you send them as JPG? The accounting system doesn't open HEIC."
You don't want to install anything, and you definitely don't want to upload forty client photos to a random website. You select all the HEIC files, drag them onto the converter, leave the quality on High, and hit Convert. One minute later, you have forty clean JPGs and a ZIP you can drop back into the shared drive. The client photos never left your laptop.
What you appreciate afterward is that nobody had to change their workflow to accommodate your phone's default format.