The CD-RW is, I suppose, taking over as a bootable and backup drive, BUT:
In boot mode, you can't write!
And some miserable jerks expect you to run a CD-RW on the native WinXP facilities, and do not provide software capable of making a bootable CD.
USB pendrives/ card readers are generally not usable as boot media.
Now whatever happened to all the "better than floppy" drives that were (possibly) bootable (with bios support), and had worthwhile capacity.
One time, the Zip drive looked favourite, and was an original fitment on some PC ranges - but the unreliability of the media and drives - "Click of Death" put paid to that.
The LS120, I liked - especially as it combined standard floppy, and high capacity in one.
Sony, had another - HiFD, that looked great on it's statistics, but seems to be vapourware.
Main problem with all the "floppy-like" devices - horrendously expensive media of only 20, 100, 120, 250 Mb capacity.