I find floppies to be very temperamental in use.
I bought my '96 Haas VF3 and had nothing but trouble with the drive. I replaced it, and the new one was quite a bit more reliable (not 100% by any means), but I had to switch to Sony media (as opposed to no-name cheap media).
I found that I could use a disk successfully but get a bad read about 5% of the time. Occasionally, the disk would go for sh!t and was totally unrecoverable. Windows could not do anything, could not even reformat it.
Since I got my wireless RS232 working over ethernet, I've had zero problems with bad files.
Since I always seem to have to reload a program at least a couple of times before I am ready for production runs, fighting with floppies several times on the same file, and then running graphics mode just to check if the file was any good, gets old fast.
Windows will also change the format of a file write without any warning. This can result in a line of 'bad code', where windows dropped a carriage return character, and you get 2 lines of nc code combined on one line. I have proven this by examining files on the hard drive, then the same file copied to a floppy, and a hex editor shows that the copy was not exactly correct on the floppy. This typically only happens on large files, like 300k in length. A full 1 meg program might have 3 or 4 such errors in it.
The graphics mode check will, of course, typically halt when it gets to some "crazy combo" line like that, but with RS 232 transfers, I've never had that happen again.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)