Someone I know who is new to macOS was trying to install Firefox recently. They'd downloaded other apps from the App Store but never installed one from a DMG. The window that pops up when you mount the Firefox DMG shows the Firefox logo, a link to the Applications folder, and an arrow going from the icon to the folder, but no further explanation (see attachment). Since my friend had never used this type of installer before, she didn't understand what to do.
Many installers include a small textual explanation in the window, like "Drag the icon to the folder to install Firefox". New users would benefit from Firefox including such an explanation. Someone is always using something for the first time.