China DOS Union

Compared with VFloppy, the advantages of GRUB for DOS/NTLDR include:

It can support floppy and hard disk images of any format, such as 360KB, 720KB, 1.44MB, 1.68MB, 2.88MB, 10MB, 50MB, and so on.
It fully supports image read and write functions, unlike VFloppy.
It fully supports various GNU GRUB usage methods and commands, is very flexible, and can also handle all kinds of parameter settings, etc.
To call GRUB from NTLDR, you only need to copy the two files GRLDR and BOOTGRUB to C:\, then add "GRUB"=C:\BOOTGRUB to BOOT.INI, and it will boot. Very simple and practical. Also, unlike VFloppy, it doesn't matter if it changes position. It can be booted just by copying the files. Is that what you call complicated?

At present its only drawback is that it must be stored contiguously, but for smaller floppy images that's not hard to deal with.

I'm afraid that the contiguous storage requirement alone is fatal enough, because if you defragment the disk, it may affect its normal operation. Also, the commands used by GRUB are relatively much more complicated. For someone familiar with Linux, of course those commands are nothing, but for a user whose English isn't very good and whose computer background is relatively weak, that probably does count as very complicated.

Climbing: You said exactly the opposite. Disk defragmentation can only make the image file remain complete and contiguous, so how could it affect it? So-called disk defragmentation is exactly to make files stored contiguously, so that GRUB can support them better and run normally! By comparison, VFloppy's support for disk defragmentation is rather poor; often once you defragment, it can no longer run. So the more often a system is defragmented, the better GRUB can run on it.

As for the GRUB command line, it's actually unnecessary, because it supports menu command file operations. If the user isn't familiar with the GRUB command line, then just copy and use an already-configured grub.conf file.