User programs—Tools such as shells, VNC clients, Web browsers, word processors, and more could all theoretically be written for EFI. In practice, of course, running such programs under a full OS is probably advantageous; but there is something to be said for running some programs from EFI. A dedicated VNC thin-client computer, for instance, could boot into the thin client very quickly if it were written for EFI. To the best of my knowledge, such tools are extremely rare under EFI at the moment.