I guess I'll need to try it. It seems like some of those old installers expected the disks to be in a certain way.
Correct, some installers will ONLY install from a floppy disk. Some check things like each disk's volume label, and many are hard coded to drive "A:".
Others, especially Microsoft products from ~1994 will take special action if they determine they are not being installed from a floppy, such as expecting sub folders in the form \disk1, \disk2, \disk3.
When using an emulator or virtualizer, ideally the software should simply give you a button or menu item to click on, that will let you specify an IMG file to use as an emulated floppy drive. But some emulators insist on making people's lives hard, so you will have to read the manual and see what obscure command they happen to use.