Amiga disks which use the crappy format thanks to different drive hardware cannot be copied using PC disk drives so more costs and effort are required to be able to do that.
It's not the drive hardware that's different, but the floppy controller. PCs use a "standard" IBM style FDC chip that is designed to read/write MFM one sector at a time, one byte at a time. The Amiga reads/writes the entire track at once, so they decided to make it work on words in the sectors so as to allow using the blitter to decode/encode the MFM. A scant few PC FDCs have raw track commands that allow reading/writing raw MFM, and those can read/write Amiga floppies just fine.
Since the Amiga read/wrote a track at once, they didn't need to worry about sector gaps. With tiny sector gaps, more data could fit in a track, which allowed the Amiga better storage. Late in the DOS age, there were PC formats with more sectors per track with smaller gaps. This allowed more data per track than normal, but you could corrupt a disk by writing to it given the smaller gaps. These formats were meant for installer software where you weren't going to write to the disks anyway, and the larger storage meant fewer disks for the install. CDs quickly supplanted this format as people would rather deal with one CD than 6 to 10 floppies.
Some Amiga games did away with the standard track format, knowing the Amiga read tracks all at once, they simply made the track one huge sector. Pysgnosis was famous for this. They also knew that Paula could track a small change in speed from the normal, so they wrote the track at a slower speed to fit more on the track than was possible writing at the standard speed (thus killing the ability to copy the disk without special hardware). Their "standard" length was about 20% larger than a normal AmigaDOS track.