External floppies are fine on Amiga 1000, 1200, 600 (using the A500 power supply or ATX on A500. A600, A1200) . On the A1000 I had the minimegs 2mg SOTS (slap on the side) adapter.
I also had the Dell High Density drive commisioned by Software hut. That unit only operated in HD mode if the internal Floppy was HD.
Most games are not extra floppy aware. Those that are make use of the extra floppies.
Once I got a big box Amiga I only used the extra drives during installations (Video Toaster floppy installs were brutal...)
