To be fair to the UI, there's also an 'Eject' option in the menu bar when you've selected the disk. There's also a keyboard shortcut. Dragging it to the trash is just more fun!
Actually, if memory serves, dragging to the trash was a shortcut for ejecting AND... what did they call it... putting it away, I think. Normal eject would leave a ghost of the floppy disk so when you inserted another one, you could copy from one floppy to another. You had to 'put away' to remove the ghost.
The Mac had a distinction between “Eject” and “Put away” mostly as a relic of the days when it had a single 400k floppy drive, so “ghost” disks were used to keep track of however many disks you needed to juggle whatever task you were doing. For example, you’d boot the computer, eject the System and insert your application, start it, then eject the application and insert your document; the system would know about all 3 disks, and whenever it needed something off a different disk it would automatically eject and prompt you to “Please insert the disk: «Name»”.
In this world, the split makes perfect sense: you eject a disk when you want the drive slot to be free, but you don’t put it away until you’re done with it. Once hard disks became standard equipment, the floppy drive was relegated to data transfer and you almost always wanted “Put away”, but renaming the menu items to what new users expected would have confused existing users.
Actually, if memory serves, dragging to the trash was a shortcut for ejecting AND... what did they call it... putting it away, I think. Normal eject would leave a ghost of the floppy disk so when you inserted another one, you could copy from one floppy to another. You had to 'put away' to remove the ghost.