Booting a live cd or installing windows at 1MByte/s speeds (late 1990s CDROMs were faster!) is horribly slow. Maybe iLO5 was a bit better.
usually found it easier (but annoying) to just walk over with a USB drive…
I've found iLO 4 virtual media support most useful for booting DOS-hosted firmware updates supplied as El Torito ISO images that aren't natively bootable from USB flash in a world where you can no longer find CD-R blanks at every corner drug store, and where newer machines commonly lack the legacy BIOS support required to boot the image at all.
It's also a fine way to boot minimal BSD or Linux rescue/netinstall images that don't involve live-booting a full desktop environment, or for installing smallish OSes like ESXi in cases where trading increased wallclock time for slightly reduced effort is justifiable.